1999 Mercury Mountaineer Differentials

Keep Your 1999 Mercury Mountaineer in Top Shape with Quality Differentials

Whether you’re repairing or upgrading your Differential, using high-quality parts is key to keeping your 1999 Mercury Mountaineer looking sharp and performing at its best. At Advance Auto Parts we carry a wide selection of dependable options, including Rear Differential Cover Gaskets, Differential Covers, and Differential Pinion Seals. Whether you’re replacing a damaged part or enhancing your truck’s style and protection, you’ll find exactly what you need to get the job done right.

Top-Rated Differentials from Trusted Brands

Looking for a reliable Differential? We’ve got you covered with options from brands you know and trust like Motive Gear, National, and Valvoline. For example, Motive Gear Differentials start at just $2.99 with an average 4.0 star rating. National and Valvoline offer similar pricing and quality, backed by strong customer feedback. With over 1,226 reviews and a solid 4 star average, you can shop with confidence knowing other Mercury Mountaineer owners approve.

Competitive Prices and Extensive Inventory

The average price for a 1999 Mercury Mountaineer Differential at Advance Auto Parts is around $211.17, with a range that starts at $1.29 and goes up to $1,539.99. With 215 options in stock from 19 trusted brands, finding the right fit is easy. Popular picks like DEX/MERC ATF Conventional Automatic Transmission Fluid, 1 Quart, Flex Fill Transmission & Differential Gear Oil: Full Synthetic 75W-90, 1 Quart, and Axle Housing Cover Gasket Rectangular Shaped, 10 Bolt Hole Gasket start at just $11.99 and offer a great balance of form and function.

Explore Related Parts

While you’re upgrading or replacing your Differential, don’t forget to check out other key components like 4WD Components and Universal Joints. At Advance Auto Parts, we’re here to help you keep your 1999 Mercury Mountaineer in peak condition, inside and out.

Essential 1999 Mercury Mountaineer Differentials

National – Axle Differential Bearing & Seal Kit (Part No.RA-311MK)

Axle Differential Bearing & Seal Kit

from

$112.99
The National bearing & seal kit includes all the components required to complete the repair.

Product Features:
  • COMPLETE SOLUTION – Includes everything needed to complete the repair
  • STRONG AND DURABLE – Controlled heat treatment process for strength and durability
  • COMPREHENSIVE COVERAGE – Industry-leading coverage for domestic and import applications
  • RIGOROUS TESTING – Comprehensive testing throughout design and development processes by National engineers for quality you can count on
  • Professional technicians know they can depend on National
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Yukon Gear – Crush Sleeve Eliminator Kit For Ford 8.8" & 7.5" (Part No.55040)

Crush Sleeve Eliminator Kit For Ford 8.8" & 7.5"

from

$96.99
2 piece solid spacer for Ford 8.8 and 7.5.

Product Features:
  • Crush sleeve eliminator kit for Ford 7.5″ and 8.8″
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Yukon Gear – Trao Loc Spring For Ford 8.8", 31 Spline (Part No.33516)

Trao Loc Spring For Ford 8.8", 31 Spline

from

$99.99
Product Features:
  • Trac Loc spring for Ford 8.8″
  • 31 spline applications only
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Yukon Gear – Carrier Installation Kit For Ford 8.8" Differential (Part No.57007)

Carrier Installation Kit For Ford 8.8" Differential

from

$134.99
Yukon Carrier installation kits are great, low cost kit for carrier changes such as Positraction or locker upgrades. Carrier installation kit for Ford 8.8″ differential. This kit contains carrier bearings, races and shims.

Product Features:
  • Fits Ford 8.8″
  • Includes carrier bearings and races and “super” carrier shim kit
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Yukon Gear – Minor Install Kit For Model 35 IFS Differential For Ranger And Explorer (Part No.12068)

Minor Install Kit For Model 35 IFS Differential For Ranger And Explorer

from

$175.99
Yukon Minimum installation kits are a low cost solution for gear changes in newer vehicles where the bearings can be reused. Includes side seals. This kit uses all high quality components to ensure a smooth set up. kit includes a pinion seal, crush sleeve (if applicable), complete shim kit, marking compound and brush.

Product Features:
  • Fits AMC Model 35 IFS
  • Included are a pinion seal, crush sleeve, complete shim kit, marking compound and brush.
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Yukon Gear – Pinion Install Kit For Ford 8.8" Differential (Part No.13041)

Pinion Install Kit For Ford 8.8" Differential

from

$167.99
Yukon Pinion installation kits are a terrific solution for gear installation on lower mileage vehicles where the carrier bearings & races can be reused. This kit uses Timken bearings and races along with a high quality pinion seal and small parts. Included in this kit are the pinion bearings and races, pilot bearing (if applicable), crush sleeve (if applicable), complete pinion shim kit, pinion nut, thread locker, and marking compound with brush. Yukon does extensive research for each application to make sure your kit will arrive with all the correct parts you need to install your pinion gear.

Product Features:
  • Fits 2009 and down Ford 8.8″
  • Included are pinion bearings and races, pinion seal, crush sleeve , complete pinion shim kit, and marking compound with brush.
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Driveworks – Oil Seal (Part No.S-714675)

Oil Seal

from

$10.99
Value-priced seal meets all cataloged application requirements.

Product Features:
  • Brand may vary by location
See More

Yukon Gear – Positraction Shim Kit (18 Shims) For GM 8.2", GM 8.5", 12T, 12P, Ford 8.8" & Cast Iron ‘Vette (Part No.16042)

Positraction Shim Kit (18 Shims) For GM 8.2", GM 8.5", 12T, 12P, Ford 8.8" & Cast Iron 'Vette

from

$41.99
Product Features:
  • Shim kit
  • Fits Ford 8.8″, 1963-1979 Corvette, GM 12 bolt passenger car and truck, 8.2″, 8.5″ and 8.6″ Dura Grip positraction
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Yukon Gear – Zip Locker Bulkhead Fitting Kit (Part No.34000)

Zip Locker Bulkhead Fitting Kit

from

$36.99
Product Features:
  • Bulkhead fitting kit
  • Includes bulkhead fitting, outer fitting and o-ring
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Pro-King – Rear Axle Shaft Kit (Part No.AXK-225)

Rear Axle Shaft Kit

from

$191.99
Pro-King is the leading supplier of transmission and driveline products in the aftermarket. All products are designed to meet or exceed OE quality, form, fit and funtion.

Product Features:
  • High strength steel
  • Dual heat treating process
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Yukon Gear – Trac Loc Positraction, Ford 8.8", 31 Spline (Part No.20069)

Trac Loc Positraction, Ford 8.8", 31 Spline

from

$719.99
Product Features:
  • Trac Loc positraction
  • Fits Ford 8.8″ with 31 spline axles
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Yukon Gear – Set Up Bearing (Part No.56042)

Set Up Bearing

from

$153.99
Set-up bearing (one bearing.) HM88648. No return.

Product Features:
  • Set up bearing
  • Fits HM88648 pinion bearing
  • Easily slips on and off pinion journal to allow for pinion depth adjustment
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National – Bearing Race (Part No.HM88610)

Bearing Race

from

$15.49
Manufactured with premium-grade steel, National taper bearing cups feature crowned raceways to ensure even load distribution.

Product Features:
  • PREMIUM MATERIALS – Precision manufactured using premium-grade steel for outstanding durability and performance
  • SMOOTH ROTATION – Crowned raceways for even load distribution
  • OE-STYLE DESIGN – Engineered to meet OE specifications
  • COMPREHENSIVE COVERAGE – Industry-leading coverage for domestic and import applications
  • RIGOROUS TESTING – Comprehensive testing throughout design and development processes by National engineers for quality you can count on
See More

Yukon Gear – Standard Open Spider Gear Kit For 8.8" Ford (And IFS) With 28 Spline Axles (Part No.16019)

Standard Open Spider Gear Kit For 8.8" Ford (And IFS) With 28 Spline Axles

from

$285.99
Yukon standard open spider gear kit for 8.8″ Ford (and IFS) with 28 spline axles and 3/4″ pin. Yukon uses higher quality materials and better techniques than OEM to ensure a longer lasting spider gear set. All components come with a one year warranty against manufacturing defects.

Product Features:
  • Spider gear kit
  • Fit Ford 8.8″ open differential with 28 spline axles
  • Includes two side gears, two pinion gears, cross pin shaft, cross pin bolt and spider gear thrust washers.
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Yukon Gear – Dana 30 Side Gear Thrust Washer (Part No.33284)

Dana 30 Side Gear Thrust Washer

from

$10.99
Dana 25, Dana 27, & Dana 30 side gear Thrust washer.

Product Features:
  • Side gear thrust washer for Dana Spicer 25, 27, 30 and AMC Model 35
  • 1.560″ I.D.
  • Fits standard open differentials only
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Yukon Gear – 14 Plate Duragrip Composite Clutches For GM 8.2", GM 8.5", 12T, 12P, Ford 8.8" & Cast Iron ‘Vette (Part No.16064)

14 Plate Duragrip Composite Clutches For GM 8.2", GM 8.5", 12T, 12P, Ford 8.8" & Cast Iron 'Vette

from

$373.99
Product Features:
  • Clutch kit
  • Fits Ford 8.8″, 1963-1979 Corvette, GM 12 bolt passenger car and truck, 8.2″, 8.5″ and 8.6″ Dura Grip positraction
  • 14 piece kit
  • Composite clutches
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Yukon Gear – Cross Pin Bolt (Part No.33067)

Cross Pin Bolt

from

$6.99
Cross pin bolt for Chrysler 8.25″, 9.25″ rear, Ford 7.5″, 8.8″, GM 12 bolt car & truck, 7.2″ IFs, 7.5″, 7.6″, 8.0″, 8.25″ IFS & 8.5″.

Product Features:
  • Cross pin bolt for Chrysler 8.25″ and 9.25″ rear, Ford 7.5″ and 8.8″, GM 12 botl car and truck, 8.5″, 8.25″ IFS, 8.0″, 7.625″, 7.5″ and 7.2″ IFS
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Idemitsu – Type HP Automatic Transmission Fluid , 1 Quart (Part No.10107-042F)

Type HP Automatic Transmission Fluid , 1 Quart

from

$10.29
Formulated to meet the specific requirements of Subaru vehicles equipped with conventional (non-CVT) transmissions up to model year 2005. Recommended for service-fill in all Subaru automatic transmissions where SUBARU ATF HP is specified. Fuel economy demands and more sophisticated electronic controls have made automatic transmissions not only more complex, but also unique to each vehicle manufacturer. Long gone are the days of having just a couple choices of automatic transmission fluid type. Idemitsu is the factory fill Automatic Transmission Fluid (ATF) supplier to most Asian imports. Idemitsu application-specific ATF products match the exact friction materials and performance requirements of each different vehicle model for which they are made.

Product Features:
  • Excellent resistance to oxidation and thermal breakdown provide long fluid life and extended protection
  • Precisely engineered frictional characteristics guarantee smooth shifting and outstanding anti-shudder performance
  • Excellent resistance to oxidation and thermal breakdown provide long fluid life and extended protection
  • Excellent seal compatibility and conditioning reduces risk of fluid leaks due to seal shrinkage, hardening and cracking
  • Advanced anti-wear technology provides maximum protection to gears and bearings
  • Precisely engineered frictional characteristics guarantee smooth shifting and outstanding anti-shudder performance
  • Provides superior cleanliness, maintaining the transmission free of sludge and varnish deposits
  • Excellent seal compatibility and conditioning reduces risk of fluid leaks due to seal shrinkage, hardening and cracking
  • Advanced anti-wear technology provides maximum protection to gears and bearings
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Powertrax – Grip LOK Traction System (Part No.LK443527)

Grip LOK Traction System

from

$681.99
For vehicles that are driven daily, the Powertrax No-Slip Traction System is the latest design in quiet traction-adding differential technology. It combines the automatic street-friendly smooth operation of a limited-slip differential with the traction performance of a locking differential. The Powertrax No-Slip locker easily installs in to your differential carrier using basic tools and without affecting your ring and pinion settings. Powertrax Grip-Lok, Lock-Right Lockers and No-Slip Traction Systems automatically provide 100% traction on-demand, under the toughest circumstances. The Powertrax Grip-Pro and Grip-LS performance limited slips offer smooth dependable torque transfer and traction for the best of both worlds!
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Yukon Gear – Pinion Gear And Thrust Washer (0.750" Shaft) For 8.8" Ford (Part No.33297)

Pinion Gear And Thrust Washer (0.750" Shaft) For 8.8" Ford

from

$8.99
Pinion gear thrust washer (0.750″ shaft) for 8.8″ Ford.

Product Features:
  • Pinion gear thrust washer
  • Fits Ford 8.8″
  • 0.750″ I.D.
See More

Yukon Gear – 7.5", 8", 8.8", 9", 10.25" Ford Redi Sleeve Yoke Saver (Part No.30226)

7.5", 8", 8.8", 9", 10.25" Ford Redi Sleeve Yoke Saver

from

$30.99
7.5″, 8″, 8.8″, 9″, 10.25″ Ford REDI sleeve yoke saver.Yukon Mighty seal.

Product Features:
  • Redi-Sleeve yoke saver
  • Fits Ford 7.5″, 8.8″, 9″ and 10.25″
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Yukon Gear – Replacement Ring Gear Bolt For Model 20, Grand Cherokee 35, "Super" Dana 30 & Dana 50 – 7/16" X 20 (Part No.33040)

Replacement Ring Gear Bolt For Model 20, Grand Cherokee 35, "Super" Dana 30 & Dana 50 - 7/16" X 20

from

$3.99
Replacement ring gear bolt for Model 20, Grand Cherokee 35, “Super” Dana 30 & Dana 50. 7/16″ x 20.

Product Features:
  • Ring gear bolt for AMC Model 20, “Super” 35, Dana Spicer “Super” 30 and Dana Spicer 50
  • 7/16″ 20 thread
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Sealed Power – Engine Auxiliary Shaft Bearing Set (Part No.1881M)

Engine Auxiliary Shaft Bearing Set

from

$36.99
Sealed Power parts provide innovative designs, use leading-edge materials and utilize ISO & QS certified manufacturing in order to deliver top quality products that meet the rigorous demands of today’s modern engines.

Product Features:
  • Steel-backed Babbitt lining material
  • Used in automotive and high-performance
  • Babbitt is designed to perform under extreme loads without damaging other engine parts
  • Babbitt is more environmentally friendly than other material
  • ISO & QS certified manufacturing
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Yukon Gear – Bearing Race Driver (Part No.56022)

Bearing Race Driver

from

$188.99
Bearing race driver. No return.

Product Features:
  • Bearing race driver
  • Fits M86610 race
  • All steel construction
See More

Yukon Gear – Super Carrier Shim Kit For Ford 8.8", GM 12 Bolt Car & Truck, 8.6 & Vette (Part No.55002)

Super Carrier Shim Kit For Ford 8.8", GM 12 Bolt Car & Truck, 8.6 & Vette

from

$59.99
Product Features:
  • Super carrier shim kit for Ford 8.8″, GM 12 bolt passenger car and truck, GM 8.0″, 8.6″, 8.6″ IRS and 1963-1979 Corvette
  • Interlocking design makes installation much easier
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Dorman – Differential Cover (Part No.697-702)

Differential Cover

from

$41.99
This direct replacement differential cover matches the fit and function of the original equipment diff cover for a reliable, leak-free repair. It features a durable design, made to strict specifications, to help ensure reliable service life.

Product Features:
  • Direct replacement – this differential cover matches the fit and function of the original equipment diff cover on select vehicles
  • Reliable repair – the smart solution for fixing an existing cover that’s rusted, damaged or leaking differential fluid
  • Durable construction – this differential cover is made according to strict engineering standards to help ensure dependability
  • Trustworthy quality – backed by a team of product experts in the United States and more than a century of automotive experience
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Dorman – Help – Differential Shaft Lock Bolt (Part No.81048)

Differential Shaft Lock Bolt

from

$6.79
This differential pinion shaft lock bolt is designed to match the fit and function of the original part on specified vehicles. Made of quality materials, it is engineered for reliable performance.

Product Features:
  • Direct replacement – this differential pinion shaft lock bolt matches the fit and function of the factory part on specified years, makes and models
  • Ideal solution – this bolt is a reliable replacement for an original part that is missing or has failed due to fatigue
  • Durable construction – this part is made from quality materials to ensure reliable performance and long service life
  • Trustworthy quality – backed by team of product experts in the United States and more than a century of automotive experience
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Yukon Gear – Dana 30 / 44 Roll Pin Replacement (Part No.33312)

Dana 30 / 44 Roll Pin Replacement

from

$12.99
Dana 30 & Dana 44 roll PIN, 0.235″ DIA, for cross pin shaft.

Product Features:
  • Roll pin for Dana Spicer 30 and Dana Spicer 44
  • 0.235″ diameter
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Most Popular Rear Differential Cover Gaskets for 1999 Mercury Mountaineers

Enhance your 1999 Mercury Mountaineer with one of the 3 Rear Differential Cover Gaskets we have in stock, starting at just $4.99.

Felpro – Axle Housing Cover Gasket Rectangular Shaped, 10 Bolt Hole Gasket (Part No.RDS 55341)

Axle Housing Cover Gasket Rectangular Shaped, 10 Bolt Hole Gasket

from

$15.99
Fel-Pro gaskets are specifically designed for the repair environment to deliver a reliable seal on even the most troublesome applications. Designed for imperfect sealing surfaces and manufactured with proprietary materials, you can count on Fel-Pro for innovative sealing solutions for the real-world repair environment.

Product Features:
  • Meets or exceeds all original equipment specifications
  • Application specific design to ensure a perfect fit
  • Engineered for the sealing repair environment
  • Validated for fit, form and function
  • Unsurpassed quality you can trust
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Yukon Gear – 8.8" Ford Cover Gasket (Part No.23011)

8.8" Ford Cover Gasket

from

$12.99
8.8″ Ford cover gasket.

Product Features:
  • Cover gasket
  • Fits Ford 8.8″
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Pro-King – Differential Cover Gasket (Part No.762B303)

Differential Cover Gasket

from

$4.99
Pro-King is the leading supplier of transmission and driveline products in the aftermarket.

Product Features:
  • All products are designed to meet or exceed OE quality, form, fit and funtion.
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Best-Selling 1999 Mercury Mountaineer Differential Covers

Upgrade your Mountaineer with one of our 6 best-selling Differential Covers, earning an average 2.75 stars rating across 35 reviews.

Dorman – Differential Cover (Part No.697-702)

Differential Cover

from

$41.99
This direct replacement differential cover matches the fit and function of the original equipment diff cover for a reliable, leak-free repair. It features a durable design, made to strict specifications, to help ensure reliable service life.

Product Features:
  • Direct replacement – this differential cover matches the fit and function of the original equipment diff cover on select vehicles
  • Reliable repair – the smart solution for fixing an existing cover that’s rusted, damaged or leaking differential fluid
  • Durable construction – this differential cover is made according to strict engineering standards to help ensure dependability
  • Trustworthy quality – backed by a team of product experts in the United States and more than a century of automotive experience
See More

ATP – DIFF COVER KIT (Part No.111103)

DIFF COVER KIT

from

$37.99
DIFF COVER KIT

Yukon Gear – Steel Cover For Ford 8.8" (Part No.32328)

Steel Cover For Ford 8.8"

from

$99.99
Yukon outer stub axle for Chrysler 9.25″ front. This axle uses a 1485 u/joint and has 33 splines.

Product Features:
  • Fits Ford 8.8″
  • Steel
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Yukon Gear – Chrome Cover For 8.8" Ford (Part No.32009)

Chrome Cover For 8.8" Ford

from

$74.99
Chrome cover for 8.8″ Ford.

Product Features:
  • Fits Ford 8.8″
  • Chrome
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Yukon Gear – 8.8" Ford Low Profile Ta HD Aluminum Rear Cover (Part No.32114)

8.8" Ford Low Profile Ta HD Aluminum Rear Cover

from

$419.99
8.8″ Ford low profile TA HD Aluminum rear Cover. This cover will not fit vehicles with independent rear suspension.

Product Features:
  • Fits Ford 8.8″
  • Aluminum girdle cover
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B & M – Rear End Cover 1 EA B&M (Part No.40297)

Rear End Cover 1 EA B&M

from

$269.99
B&M Cast Aluminum Differential Covers are designed to strengthen the differential by preventing case distortion and ring gear & bearing cap deflection. Constructed of A356.0-T6 aluminum, these rugged covers significantly increase the fluid capacity and dissipate heat much faster than the stock factory unit to prolong the life of your ring and pinion gears. Additional features include an engraved B&M logo, drain and fill port locations, a magnetic drain plug for catching ferrous metal particles, and complete hardware and installation instructions.

Product Features:
  • Additional Oil Capacity
  • More Cooling Ability
  • No Dipstick Modification
  • Some Include Fluid Pickup Extension
  • Built-In Drain Plugs
  • Cast Aluminum
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Top-Quality Differential Pinion Seals for 1999 Mercury Mountaineers

Choose a high-quality OEM or aftermarket Differential Pinion Seal for Mercury Mountaineers and enjoy top-notch performance from $5.99.

Driveworks – Oil Seal (Part No.S-3604)

Oil Seal

from

$5.99
Value-priced seal meets all cataloged application requirements.

Product Features:
  • Brand may vary by location
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Driveworks – Oil Seal (Part No.S-714675)

Oil Seal

from

$10.99
Value-priced seal meets all cataloged application requirements.

Product Features:
  • Brand may vary by location
See More

FAG US – Shaft Seal (Part No.SS2876)

Shaft Seal

from

$23.79
Our wheel seals are engineered using only the highest-quality materials to meet vehicle manufacturer specificatons. We work with suppliers to design seals that meet FAG’s quality standards. Seals are designed to protect wheel end components from contamination – such as dirt, dust, and moisture – and prevent the loss of grease over the life of the bearing. The specifications for wheel seals are very demanding, and the type required depends on the specific application, position and vehicle class.

Product Features:
  • High-precision and High-quality components used in all KITs
  • Coverage of classic and new high-tech solutions for the best system coverage
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FAG US – Shaft Seal (Part No.SS2865)

Shaft Seal

from

$15.99
Our wheel seals are engineered using only the highest-quality materials to meet vehicle manufacturer specificatons. We work with suppliers to design seals that meet FAG’s quality standards. Seals are designed to protect wheel end components from contamination – such as dirt, dust, and moisture – and prevent the loss of grease over the life of the bearing. The specifications for wheel seals are very demanding, and the type required depends on the specific application, position and vehicle class.

Product Features:
  • High-precision and High-quality components used in all KITs
  • Coverage of classic and new high-tech solutions for the best system coverage
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Yukon Gear – Pinion Seal For 7.5", 8.8", And 9.75" Ford, And Also 1985-’86 9" Ford (Part No.30037)

Pinion Seal For 7.5", 8.8", And 9.75" Ford, And Also 1985-'86 9" Ford

from

$8.99
Pinion seal for 7.5″, 8.8″, and 9.75″ Ford, and also 1985-’86 9″ Ford.Yukon Mighty seal.

Product Features:
  • Pinion seal
  • Fits Ford 7.5″, 8.8″ and some 9.75″
  • 2.785″ O.D.
See More

Top Picks for 1999 Mercury Mountaineer Differential Oil

Invest in one of our 8 durable Differential Oil for your 1999 Mercury, knowing you’re getting trusted brands and expert craftsmanship.

Valvoline – DEXRON – VI ATF Full Synthetic Automatic Transmission Fluid, 1 Quart (Part No.822405)

DEXRON - VI ATF Full Synthetic Automatic Transmission Fluid, 1 Quart

from

$14.49
Valvoline DEXRON-VI/MERCON LV ATF is a full-synthetic transmission fluid formulated with advanced additive technology to meet and exceed the requirements of the General Motors DEXRON-VI specification. It is officially licensed and approved by GM and is fully back-serviceable and can be used wherever DEXRON-II and/or DEXRON-III are recommended. Recommended for use in the following applications: DEXRON-VI, DEXRON-III, DEXRON-II, and Allison C-4.

Product Features:
  • Formulated with full-synthetic base stocks and advanced additive technology to meet the challenging demands of automatic transmissions
  • Enhanced anti-shudder protection for smooth shifting and maximum power transfer
  • Developed with anti-wear technology to help improve transmission durability
  • Engineered with a proprietary blend of base oils and advanced additives to provide better oil flow at low temperatures and greater film protection at higher temperatures
See More

Valvoline – SynPower Transmission & Differential Gear Oil: Full Synthetic 75W-140, 1 Gallon (Part No.887344)

SynPower Transmission & Differential Gear Oil: Full Synthetic 75W-140, 1 Gallon

from

$69.99
Valvoline SAE 75W-140 Full Synthetic Gear Oil provides the ultimate gear protection in hypoid rear differentials and non-synchronized manual transmissions. Engineered to outperform, our formulation provides exceptional high and low temperature protection and excellent thermal stability, especially in demanding driving situations such as towing and off-roading. It contains an extreme pressure additive for better load carrying capacity and wear resistance, a limited slip additive for optimal clutch pack performance, and an anti-foaming agent for better lubrication and service life. It’s recommended for conventional rear axles and transmissions requiring EP gear lubes under high speed, high load, high torque and high horsepower conditions.

Product Features:
  • EXCEPTIONAL HIGH AND LOW TEMPERATURE PROTECTION ranging from -22F to 390F degrees
  • REDUCES CHATTERING AND PROTECTS GEAR TEETH from oxidation, rust, and wear
  • FIGHTS CORROSION AND RUST with emulsifying agents and safeguards against impurities, oxidation and thermal breakdown
  • MEETS THE DEMANDS OF CONVENTIONAL AND LIMITED SLIP REAR DIFFERENTIALS where API GL-5 is specified, as well as non-synchronized manual transmissions that require API GL-4
  • MEETS OR EXCEEDS PERFORMANCE REQUIREMENTS for Ford M2C-192A, GM 12346140, Chrysler MS-8985 and API GL-5
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Valvoline – DEX/MERC ATF Conventional Automatic Transmission Fluid, 1 Quart (Part No.798153)

DEX/MERC ATF Conventional Automatic Transmission Fluid, 1 Quart

from

$11.99
Valvoline DEX/MERC ATF is a high-quality transmission fluid formulated to meet the challenging demands of many automatic transmissions. Its responsive low-temperature fluidity is beneficial in both electronic and hydraulic controlled transmissions and transaxles. Recommended for use in the following applications: MERCON*, DEXRON*-III, Ford M2C138-CJ and M2C166-H, Allison C-4 and TES-389, and Caterpillar TO-2.

Product Features:
  • Formulated with premium base stocks and advanced additive technology to meet the challenging demands of automatic transmissions
  • Enhanced anti-shudder protection for smooth shifting and maximum power transfer
  • Developed with anti-wear technology to help improve transmission durability
  • Engineered with a proprietary blend of base oils and advanced additives to provide better oil flow at low temperatures and greater film protection at higher temperatures
See More

Valvoline – Flex Fill Transmission & Differential Gear Oil: Full Synthetic 75W-90, 1 Quart (Part No.889785)

Flex Fill Transmission & Differential Gear Oil: Full Synthetic 75W-90, 1 Quart

from

$18.99
We’ve squeezed innovation into every ounce of Valvoline FlexFill SAE 75W-90 Full Synthetic Gear Oil, the ultimate gear protection in hypoid rear differentials and non-synchronized manual transmissions. Our unique new flexible pouch makes getting into the tightest places to lubricate gears easier than ever and with less waste. The superior detergent package-based formulation contains fully synthetic basestocks and special additives that help protect parts from rust and corrosion while providing exceptional high and low temperature protection and excellent thermal stability, especially in demanding driving situations such as towing and off-roading. It contains an extreme pressure additive for better load carrying capacity, wear resistance additives that assist in protecting gear teeth, a limited slip additive for optimal clutch pack performance, and an anti-foaming agent for better lubrication and service life. Valvoline FlexFill SAE 75W-90 Full Synthetic Gear Oil is recommended for use in axle applications requiring factory-fill or drain-and-fill levels for limited slip performance.

Product Features:
  • FLEXIBLE POUCH FOR EASIER USE WITH LESS WASTE in tight, hard to reach undercarriage situations.
  • EXCEPTIONAL HIGH AND LOW TEMPERATURE PROTECTION ranging from -30F to 300F degrees for dependable coverage year-round
  • REDUCES CHATTERING AND PROTECTS GEAR TEETH from oxidation, rust, and wear
  • MEETS THE DEMANDS OF CONVENTIONAL AND LIMITED SLIP REAR DIFFERENTIALS where API GL-5 is specified, as well as non-synchronized manual transmissions that require API GL-4 or MT-1 fluid
  • MEETS OR EXCEEDS PERFORMANCE REQUIREMENTS for Mack GO-H and GO-J; API GL-5 and API MT-1; MIL-PRF-2105E; and SAE J2360
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Yukon Gear – Redline Synthetic "Shock Proof" Oil With Positraction Additive – 4 Quarts (Part No.15005)

Redline Synthetic "Shock Proof" Oil With Positraction Additive - 4 Quarts

from

$148.99
Redline Synthetic “Shock Proof” Oil with positraction Additive. 4 Quarts.

Product Features:
  • Includes four quarts of Redline Shockproof oil and one 4oz bottle of Yukon positraction additive
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Yukon Gear – Redline Synthetic "Shock Proof" Oil – 3 Quarts (Part No.15000)

Redline Synthetic "Shock Proof" Oil - 3 Quarts

from

$99.99
Redline Synthetic “Shock Proof” Oil. 3 Quarts.

Product Features:
  • Includes three quarts of Redline Shockproof oil
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Yukon Gear – Redline Synthetic "Shock Proof" Oil – 4 Quarts (Part No.15004)

Redline Synthetic "Shock Proof" Oil - 4 Quarts

from

$137.99
Redline Synthetic “Shock Proof” Oil. 4 Quarts.

Product Features:
  • Includes four quarts of Redline Shockproof oil
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Idemitsu – Type HP Automatic Transmission Fluid , 1 Quart (Part No.10107-042F)

Type HP Automatic Transmission Fluid , 1 Quart

from

$10.29
Formulated to meet the specific requirements of Subaru vehicles equipped with conventional (non-CVT) transmissions up to model year 2005. Recommended for service-fill in all Subaru automatic transmissions where SUBARU ATF HP is specified. Fuel economy demands and more sophisticated electronic controls have made automatic transmissions not only more complex, but also unique to each vehicle manufacturer. Long gone are the days of having just a couple choices of automatic transmission fluid type. Idemitsu is the factory fill Automatic Transmission Fluid (ATF) supplier to most Asian imports. Idemitsu application-specific ATF products match the exact friction materials and performance requirements of each different vehicle model for which they are made.

Product Features:
  • Excellent resistance to oxidation and thermal breakdown provide long fluid life and extended protection
  • Precisely engineered frictional characteristics guarantee smooth shifting and outstanding anti-shudder performance
  • Excellent resistance to oxidation and thermal breakdown provide long fluid life and extended protection
  • Excellent seal compatibility and conditioning reduces risk of fluid leaks due to seal shrinkage, hardening and cracking
  • Advanced anti-wear technology provides maximum protection to gears and bearings
  • Precisely engineered frictional characteristics guarantee smooth shifting and outstanding anti-shudder performance
  • Provides superior cleanliness, maintaining the transmission free of sludge and varnish deposits
  • Excellent seal compatibility and conditioning reduces risk of fluid leaks due to seal shrinkage, hardening and cracking
  • Advanced anti-wear technology provides maximum protection to gears and bearings
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Top-Rated Differential Bearings for 1999 Mercury Mountaineers

Make a smart move for your 1999 Mercury Mountaineer with products all priced from $6.99 to $27.99.

National – Bearing Race (Part No.LM501314)

Bearing Race

from

$9.29
Manufactured with premium-grade steel, National taper bearing cups feature crowned raceways to ensure even load distribution.

Product Features:
  • PREMIUM MATERIALS – Precision manufactured using premium-grade steel for outstanding durability and performance
  • SMOOTH ROTATION – Crowned raceways for even load distribution
  • OE-STYLE DESIGN – Engineered to meet OE specifications
  • COMPREHENSIVE COVERAGE – Industry-leading coverage for domestic and import applications
  • RIGOROUS TESTING – Comprehensive testing throughout design and development processes by National engineers for quality you can count on
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National – Multi-Purpose Bearing (Part No.A-36)

Multi-Purpose Bearing

from

$27.99
Product Features:
  • CONSISTENT PERFORMANCE: Matched cup and cone components ensure consistent performance
  • PREMIUM MATERIALS: Precision manufactured using premium-grade steel for outstanding durability and performance
  • SMOOTH ROTATION: Crowned raceways and rollers for even load distribution
  • OE-STYLE DESIGN: Engineered to meet OE specifications
  • COMPREHENSIVE COVERAGE: Industry-leading coverage for domestic and import applications
  • RIGOROUS TESTING: Comprehensive testing throughout design and development processes by National engineers for quality you can count on
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National – Tapered Roller Bearing Cone (Part No.LM501349)

Tapered Roller Bearing Cone

from

$19.99
Manufactured with premium-grade steel, National taper bearing cones feature crowned raceways and rollers to ensure even load distribution.

Product Features:
  • PREMIUM MATERIALS – Precision manufactured using premium-grade steel for outstanding durability and performance
  • SMOOTH ROTATION – Crowned raceways and rollers for even load distribution
  • OE-STYLE DESIGN – Engineered to meet OE specifications
  • COMPREHENSIVE COVERAGE – Industry-leading coverage for domestic and import applications
  • RIGOROUS TESTING – Comprehensive testing throughout design and development processes by National engineers for quality you can count on
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FAG US – Bearing – DGBB (Deep Groove Ball Bearing) (Part No.6208-C3)

Bearing - DGBB (Deep Groove Ball Bearing)

from

$24.79
We develop and produce high-quality roller bearings, spherical bearings, and plain bearings worldwide for a wide range of applications.

Product Features:
  • Radial Ball Bearing, Both Sides Shield.
  • Coverage of classic and new high-tech solutions for the best system coverage
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FAG US – Bearing – TRB (Tapered Roller Bearing) (Part No.KT5)

Bearing - TRB (Tapered Roller Bearing)

from

$21.29
With advanced load-carrying capacity and compact design, tapered roller bearings are used in wheel bearings, transmissions, differentials, transfer cases and other miscellanous applications. FAG manufacturers over 100 million tapered roller bearings annually.

Product Features:
  • High-precision and High-quality components used in all KITs
  • Coverage of classic and new high-tech solutions for the best system coverage
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FAG US – Cup (Part No.M88010)

Cup

from

$11.29
With advanced load-carrying capacity and compact design, tapered roller bearings are used in wheel bearings, transmissions, differentials, transfer cases and other miscellanous applications. FAG manufacturers over 100 million tapered roller bearings annually.

Product Features:
  • High-precision and High-quality components used in all KITs
  • Coverage of classic and new high-tech solutions for the best system coverage
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Yukon Gear – Cross Pin Bolt (Part No.33067)

Cross Pin Bolt

from

$6.99
Cross pin bolt for Chrysler 8.25″, 9.25″ rear, Ford 7.5″, 8.8″, GM 12 bolt car & truck, 7.2″ IFs, 7.5″, 7.6″, 8.0″, 8.25″ IFS & 8.5″.

Product Features:
  • Cross pin bolt for Chrysler 8.25″ and 9.25″ rear, Ford 7.5″ and 8.8″, GM 12 botl car and truck, 8.5″, 8.25″ IFS, 8.0″, 7.625″, 7.5″ and 7.2″ IFS
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Top-Rated Differential Brands For Your 1999 Mercury Mountaineer

When it comes to finding the perfect Differential for your 1999 Mercury Mountaineer, Advance Auto Parts has you covered with a wide selection of high-quality OEM and aftermarket options from 19 trusted brands. We carry the most popular Differential brands including Valvoline, National, and Motive Gear, and more, all known for their exceptional customer ratings (average brand rating of 4.8 stars) and competitive prices, as low as $2.99. Purchasing a Differential from us here at Advance Auto Parts is a smart move for both you and your 1999 Mercury Mountaineer, providing peace of mind with parts that meet or exceed OEM standards.

Popular Valvoline 1999 Mercury Mountaineer Differentials

If you’re looking for a top-quality Differential for your 1999 Mercury Mountaineer, Advance Auto Parts has exactly what you need with our selection of Valvoline Differentials. We have 2 Valvoline Differentials in stock for this fitment, all known for their durability and precision fit. With prices starting at just $14.49 and an average cost of $42.24, you’ll find the perfect Differential for your needs and budget. Valvoline Differentials for the 1999 Mercury Mountaineer come highly rated, with over 366 customer reviews and an impressive average rating of 4.8 stars. Choosing a Valvoline Differential from Advance Auto Parts is a smart move to ensure quality and value for your vehicle.
DEXRON - VI ATF Full Synthetic Automatic Transmission Fluid, 1 Quart
from $14.49
(2)
DEXRON – VI ATF Full Synthetic Automatic Transmission Fluid, 1 Quart
“I’ve used this in my 2005 2500HD since I bought the truck with 20k on it now at 280k changed every other year maybe 40k I’d put on in two years, I pu”

Top-Quality National 1999 Mercury Mountaineer Differentials

For those in search of a high-quality Differential for their 1999 Mercury Mountaineer, Advance Auto Parts offers a great selection of National Differentials. With 3 National Differentials in stock, you can trust you’re getting top-tier parts designed for durability and a perfect fit. Prices for these Differentials start at just $7.99, with an average price of $11.42, giving you a range of options to suit your budget. Backed by over 45 customer ratings and an average rating of 4.3 stars, National Differentials provide both reliability and excellent performance. Choosing a National Differential from Advance Auto Parts is a smart investment in your vehicle’s performance and longevity.
Bearing Race
from $9.29
(2)
Bearing Race
“Reasonable price and woks well. front diff 2006 Escalade esv”
Multi-Purpose Bearing
from $16.99
(39)
Multi-Purpose Bearing
“Great bearings”
Bearing Race
from $7.99
(4)
Bearing Race
“Goes with M88010 bearing cup. Application was the pinion bearing race for a Ford 9 Inch on a 1957 Ford F-100.”

FAQs for 1999 Mercury Mountaineer Differentials

What are the best-selling Differentials for 1999 Mercury Mountaineers?

Out of 215 Differentials that fit 1999 Mercury Mountaineers, the following parts are the top sellers:

What’s the price range for 1999 Mercury Mountaineer Differentials?

The prices of Differentials for the 1999 Mercury Mountaineer range from $1.29 up to $1,539.99 for the most premium parts.

What is the average price of a Differential for a 1999 Mercury Mountaineer?

The average price for Differentials for the 1999 Mercury Mountaineer is $211.17. Keep in mind the variety of part types within our Differential category, where you are likely to find a wide range of prices across a variety of parts and components.

Does Advance Auto Parts sell Differentials for other Mercury Mountaineer model years?

Yes, we carry Differentials for 12 model years of Mercury Mountaineers between 1997 and 2010. The following model years are the most popular for Differential purchases: 2010, 2009, 2008, 2007, 2006, 2005, 2004, 2003, and 2002.

What are the cheapest Differentials for my 1999 Mercury Mountaineer?

The cheapest 1999 Mercury Mountaineer Differentials we carry are:

Does Advance Auto Parts sell Differentials for any other 1999 Mercury models?

Yes. We stock Differentials for 5 other popular 1999 Mercury models. Some of the most popular are 1999 Cougar Differentials, 1999 Grand Marquis Differentials, 1999 Tracer Differentials, 1999 Mystique Differentials, and 1999 Sable Differentials.

What are the top-rated Differentials that fit the 1999 Mercury Mountaineer?

The one 1999 Mercury Mountaineer Differential we have in stock is the Differential Ring Gear Bolt. It costs $1.29.

What types of Differentials do you sell for my 1999 Mercury Mountaineer?

As of 11/2/25, these are some of the most in-demand types of Differentials for a 1999 Mercury Mountaineer:

Can I get help with 1999 Mercury Mountaineer Differential orders?

Contact our customer support team by chat or phone, through the help desk page, where you can find instant answers about Mercury Differentials and more.

What is your return policy for Mercury Mountaineer Differentials?

Advance Auto Parts keeps returns simple. For new Mercury Mountaineer Differentials and accessories, your online orders can be returned, in their original condition, within 45 days. For requirements, see the returns page.