1979 Mercury Cougar Differentials

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Keep Your 1979 Mercury Cougar in Top Shape with Quality Differentials

Whether you’re repairing or upgrading your Differential, using high-quality parts is key to keeping your 1979 Mercury Cougar looking sharp and performing at its best. At Advance Auto Parts we carry a wide selection of dependable options, including Differential Bearings, Rear Differential Cover Gaskets, and Differential Oil. 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 National, Powertrax, and Felpro. For example, National Differentials start at just $7.29 with an average 4.3 star rating. Powertrax and Felpro offer similar pricing and quality, backed by strong customer feedback. With over 96 reviews and a solid 4 star average, you can shop with confidence knowing other Mercury Cougar owners approve.

Competitive Prices and Extensive Inventory

The average price for a 1979 Mercury Cougar Differential at Advance Auto Parts is around $259.42, with a range that starts at $1.99 and goes up to $1,211.99. With 402 options in stock from 16 trusted brands, finding the right fit is easy. Popular picks like 3 Qt – 80W90 Conventional Gear Oil with Posi Additive, 3 Qt – Penzoil 80W90 Conventional Gear Oil, and Cover Bolt For Ford 7.5", 8.8" & 9.75" start at just $6.99 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 Drive Shafts and Axles and Universal Joints. At Advance Auto Parts, we’re here to help you keep your 1979 Mercury Cougar in peak condition, inside and out.

Essential 1979 Mercury Cougar Differentials

Powertrax – Differential Lock Assembly (Part No.9206883108)

Differential Lock Assembly

from

$544.99
For vehicles that are driven daily, the Power Trax 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 Power Trax No-Slip locker easily installs in to your differential carrier using basic tools and without affecting your ring and pinion settings. Power Trax Grip-Lok, Lock-Right Lockers and No-Slip Traction Systems automatically provide 100% traction on-demand, under the toughest circumstances. The Power Trax Grip-Pro and Grip-LS performance limited slips offer smooth dependable torque transfer and traction for the best of both worlds.

Product Features:
  • The Power Trax Lock-Right Locker provides outstanding traction for off-road machines and race vehicles. Power Trax No-Slip Traction Systems deliver excellent performance to street-driven cars and trucks.
  • Power Trax lockers range from the original, Lock-Right for serious straight-line performance, to the No-Slip traction system for street-able vehicles.
  • Power Trax offers three levels of GRIP locking differentials, ranging from the clutch-type GRIP LS with a forged steel case, the gear-driven GRIP PRO and finally the GRIP LOK for extreme traction.
  • Power Trax ia an Extreme Traction System
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National – Axle Differential Bearing & Seal Kit (Part No.RA-311)

Axle Differential Bearing & Seal Kit

from

$169.99
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 – Trac Loc For Ford 9" Wtih 28 Spline Axles – Aggressive Design (Part No.26007)

Trac Loc For Ford 9" Wtih 28 Spline Axles - Aggressive Design

from

$821.99
The Yukon Dura Grip provides aggressive yet smooth traction to give you the confidence & performance you need. Get longer life and better traction with the heavy duty Yukon Dura Grip Positraction. The Yukon Trac Loc uses a nodular case, billet side hat, and forged internals for higher strength than stock Trac-Locs. The units use composite clutches for high performance and long life. All units are Rebuildable. Yukon offers a one year warranty against manufacturing defects.

Product Features:
  • Fits Ford 9″ with 28 spline axles
  • Trac Loc positraction
  • Clutch style positraction
  • Aggressive design
  • Internal gears are manufactured using forged 4320 steel and cut to provide stronger teeth
  • Fully rebuildable
  • Assembled in the USA
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Yukon Gear – Outer Oil Slinger For Ford 7.5", 8.8", 9", 10.25" (Part No.33022)

Outer Oil Slinger For Ford 7.5", 8.8", 9", 10.25"

from

$8.99
Replacement outer oil slinger for Ford 7.5″, 8.8″, 9″, 10.25″, Nissan Titan rear, Dana 44 Rubicon & 44 JK non-Rubicon.

Product Features:
  • Outer oil slinger for Ford 10.25″, 7.5″, 8.8″ and 9″ also Jeep JK and Nissan Titan rear
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USA Standard Gear – Differential Spider Gear Kits (Part No.39018)

Differential Spider Gear Kits

from

$249.99
Replacement ring gear bolt for Dana 80. 9/16″ x 18.

Product Features:
  • Spider gear kit
  • Fits Ford 9″ 31 spline open differential
  • Includes two side gears, four pinion gears, cross pin shaft, roll pins and spider gear thrust washers.
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Yukon Gear – Standard Open Spider Gear Kit for 7.5" Ford with 28 Spline Axles (Part No.16014)

Standard Open Spider Gear Kit for 7.5" Ford with 28 Spline Axles

from

$214.99
Yukon Gear & Axle spider gear kits feature higher quality materials and better manufacturing techniques than OEM to ensure a longer lasting spider gear set. Kit delivers everything needed for a complete and proper spider gear set replacement.

Product Features:
  • Spider gear kit
  • Fit Ford 7.5″ open differential
  • Includes two side gears, two pinion gears, cross pin shaft, cross pin bolt and spider gear thrust washers.
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Yukon Gear – 3.062" Side Adjuster for Ford 9" (Part No.32139)

3.062" Side Adjuster for Ford 9"

from

$94.99
Yukon Gear & Axle dropouts are heavy duty. They feature upgraded nodular iron construction and a larger-than-OEM design to provide unrivaled strength and reliability in racing and off-road applications.

Product Features:
  • Side adjuster
  • Fits Ford 9″
  • 3.062″ designs only
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National – Bearing Race (Part No.LM102910)

Bearing Race

from

$7.29
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
See More

Yukon Gear – Fine Thread Pinion Support Bolt (Aftermarket Aluminum Only) for 9" Ford (Part No.33243)

Fine Thread Pinion Support Bolt (Aftermarket Aluminum Only) for 9" Ford

from

$5.99
Yukon Gear & Axle manufactures a full line of top quality small parts to complete any job including ring gear bolts, crush sleeves, pinion nuts and washers, axle studs, thrust washers and much, much more. For all your differential small parts needs, look no further than Yukon.

Product Features:
  • Pinion support bolt for Ford 9″
  • 3/8″ x 24 thread
  • 1.5″ long
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National – Multi-Purpose Seal (Part No.7044NA)

Multi-Purpose Seal

from

$14.99
National has built a reputation as one of the most respected names in the industry. We have offered premium sealing solutions for more than 75 years. Our design team keeps pace with the industry and provides advanced solutions for today’s vehicles.

Product Features:
  • Design type: spring loaded; multi-lip
  • Temperature range: -40 Deg. F to 225 Deg. F / -40 Deg. C to 107 Deg. C
  • Good low temperature capability
  • Low swell in hydrocarbon fluids
  • Delivers quality and reliable performance for every type of repair
See More

Yukon Gear – Shim Kit for 9" Ford Tracloc Clutch (Part No.16030)

Shim Kit for 9" Ford Tracloc Clutch

from

$46.99
Yukon Gear & Axle manufactures a full line of top-quality small parts to complete any job including ring gear bolts, crush sleeves, pinion nuts and washers, axle studs, thrust washers, and other general maintenance items. You can count on Yukon to fulfill all your differential small parts needs.

Product Features:
  • Shim kit
  • Fits Ford 8″ and 9″ Trac Loc
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Yukon Gear – Steel Spool for Ford 9" with 35 Spline Axles (Part No.32047)

Steel Spool for Ford 9" with 35 Spline Axles

from

$379.99
Yukon Full Spools are a cost-effective way to convert a diff to 100% lockup. Installation is easy as they install in place of your differential carrier assembly. Each Yukon spool is made from high-quality 8620 steel and heat treated for additional strength. A spool is an outstanding choice for dedicated off-road and drag racing vehicles only.

Product Features:
  • Fits Ford 9″ with 35 spline axles
  • Provides 100% traction to both wheels at all times
  • Not recommended for street driven vehicles
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Yukon Gear – Pinion Depth Shims for Ford 9" with 7/16" Studs (Part No.55057)

Pinion Depth Shims for Ford 9" with 7/16" Studs

from

$76.99
Yukon shim kits are precision machined and tailored for each individual application to ensure you have the right shims for every set up.

Product Features:
  • Pinion depth shim kit
  • Fits Ford 9″ with 7/16″ pinion support bolts
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Yukon Gear – 9" Ford Pinion Nut, 35 Spline Large Pinion Oversize (Part No.33161)

9" Ford Pinion Nut, 35 Spline Large Pinion Oversize

from

$26.99
Yukon Gear & Axle manufactures a full line of top quality small parts to complete any job including ring gear bolts, crush sleeves, pinion nuts and washers, axle studs, thrust washers and much, much more. For all your differential small parts needs, look no further than Yukon.

Product Features:
  • Pinion nut
  • Fits Ford 9″ with 35 spline pinion
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Yukon Gear – Side Gear and Thrust Washer (0.750" Shaft) for 8.8" Ford (Part No.33298)

Side Gear and Thrust Washer (0.750" Shaft) for 8.8" Ford

from

$6.99
Yukon Gear & Axle manufactures a full line of top quality small parts to complete any job including ring gear bolts, crush sleeves, pinion nuts and washers, axle studs, thrust washers and much, much more. For all your differential small parts needs, look no further than Yukon.

Product Features:
  • Side gear thrust washer for Ford 8.8″
  • 0.750″ diameter cross pin shaft applications only
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Motive Gear – Ring Gear Bolt (Part No.D8OZ4216B)

Ring Gear Bolt

from

$1.99


Product Features:
  • BOLT 9″ FORD OPEN R.G. SAME AS M-4216A200
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Yukon Gear – Purple Aluminum Pinion Support for 9" Ford Daytona (Part No.32036)

Purple Aluminum Pinion Support for 9" Ford Daytona

from

$264.99
Yukon Gear & Axle manufactures a full line of top-quality small parts to complete any job including ring gear bolts, crush sleeves, pinion nuts and washers, axle studs, thrust washers, and other general maintenance items. For all your differential small parts needs, look no further than Yukon.

Product Features:
  • Anodized purple
  • 6061 aluminum
  • Larger inner pinion bearing reduces gear deflection under high load
  • Fits Ford 9″ with 28 spline pinion
  • Anodized purple
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Motive Gear – Axle Shaft Kit (Part No.MG1231)

Axle Shaft Kit

from

$149.99
The Motive Gear replacement axle shaft offers an OE-quality axle shaft at a fraction of the OE cost. Manufactured from 1541H material on high-tolerance CNC equipment, this axle shaft is designed to provide a perfect fit every time.

Product Features:
  • AXLE SHAFT 8.8″ 28 SPL. 29 1/4″ 79-93 MUSTANG L & R
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Yukon Gear – Bearing Race Driver for Ford 9", GM 10.5", & Chrysler 11.5" Differentials (Part No.56019)

Bearing Race Driver for Ford 9", GM 10.5", & Chrysler 11.5" Differentials

from

$219.99
Yukon Gear & Axle offers a full line of top quality differential tools to save time and money.

Product Features:
  • For Ford 9″, GM 10.5″, & Chrysler 11.5″ differentials
  • Fits LM104911 race
  • All-steel construction
  • For accurate installation of bearing races
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Yukon Gear – Star Washers, 3.250" Ford 9" Drop Out New Design Only (Part No.32144)

Star Washers, 3.250" Ford 9" Drop Out New Design Only

from

$4.99
Yukon Gear & Axle dropouts are heavy duty. They feature upgraded nodular iron construction and a larger-than-OEM design to provide unrivaled strength and reliability in racing and off-road applications.

Product Features:
  • Star washer
  • Fits Ford 9″
  • 3.250″ designs only
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Valvoline – MaxLife Multi-Vehicle (ATF) Full Synthetic Automatic Transmission Fluid, 1 Quart (Part No.VV324)

MaxLife Multi-Vehicle (ATF) Full Synthetic Automatic Transmission Fluid, 1 Quart

from

$12.49
Valvoline Full Synthetic MaxLife Multi-Vehicle ATF, the No. 1 ATF product, suitable for use in 95% of vehicles. And now, it’s recommended for most belt & chain-driven continuously variable transmissions (CVT). Featuring advanced additives to prevent the major causes of transmission breakdown, it’s designed to help prevent leaks, reduce wear & tear, and maximize performance. Has improved thermal stability for longer fluid life, better viscosity stability for consistent transmission operation, and frictional enhancements for smooth gear engagements. Valv MaxLife Multi-Vehicle ATF is suitable for most Ford, GM, Toyota, Honda, Nissan, Hyundai, Subaru, BMW, Mercedes, Volvo, VW & Audi vehicles. Recommended for use in: GM DEXRON-II, DEXRON-III, DEXRON-VI, and DEX-CVT; Ford MERCON LV; Toyota/Lexus Type T, T-II, T-IV, WS, CVTF FE, and CVTF TC; Honda/Acura ATF-Z1 and Honda CVT; Nissan/Infiniti Matic-D, Matic-J, Matic-K and Matic-S; Hyundai/Kia SP-II, SP-III, SP-IV and SPH-IV; BMW 7045E, ETL 8072B, LA2634 and LT71141; Allison C-4; Mercedes-Benz NAG-1; Volvo 1161521, 1161540, 97340 and 1273.41; Subaru ATF HP, Lineartronic chain CVT and CVT-II, Lineartronic High Torque CVT, and CV-30; and VW/Audi G-052-025-A2 and G-052-162-A1. CURRENTLY UNABLE TO SHIP THIS PRODUCT TO CUSTOMERS LOCATED IN CALIFORNIA

Product Features:
  • FOR USE IN 95% OF VEHICLES INCLUDING MOST CVTs in operation with US registered light duty applications
  • HIGH PERFORMANCE CONDITIONING AGENTS prolong seal elasticity to prevent leaks
  • IMPROVED DURABILITY & TRANSMISSION LIFE with anti-wear technology to avoid costly repairs
  • ENHANCED HIGH & LOW TEMP PERFORMANCE supports transmission fluid in all weather situations
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Motive Gear – Differential Carrier (Part No.D3TZ4204A)

Differential Carrier

from

$226.99


Product Features:
  • FORD 9″ EMPTY POSI CASE – 28 & 31 SPLINES
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Yukon Gear – Pinion Gear and Thrust Washer for 8" and 9" Ford, Model 20, and 7.25" Chrysler (Part No.33301)

Pinion Gear and Thrust Washer for 8" and 9" Ford, Model 20, and 7.25" Chrysler

from

$4.99
Yukon Gear & Axle manufactures a full line of top quality small parts to complete any job including ring gear bolts, crush sleeves, pinion nuts and washers, axle studs, thrust washers and much, much more. For all your differential small parts needs, look no further than Yukon.

Product Features:
  • Pinion gear thrust washer for Ford 8″, Ford 9″ and Chrysler 7.25″
See More

Yukon Gear – Pinion Setup Bearing for Popular GM, Ford, Dana, & Chrysler Differentials (Part No.56045)

Pinion Setup Bearing for Popular GM, Ford, Dana, & Chrysler Differentials

from

$153.99
Yukon Gear & Axle offers a full line of top quality differential tools to save time and money.

Product Features:
  • Easily slips on and off pinion journal to allow for easier pinion depth adjustment
  • Fits M802048 pinion bearing
  • For popular GM, Ford, Dana, and Chrysler differentials
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Yukon Gear – Dropout Housing Stud For Ford 8" & 9" (Part No.32338)

Dropout Housing Stud For Ford 8" & 9"

from

$7.99
Yukon Ring & Pinion sets give you the confidence of knowing you’re running gears designed for the harshest of conditions. Whether it’s on the street, off-road, or at the track; Yukon ring & pinion sets deliver unrivaled performance & quality. Yukon uses the latest designs and manufacturing technologies to provide a quiet running gear that is strong and easy to set up. All Yukon ring & pinion sets come standard with a one-year warranty.

Product Features:
  • Housing stud
  • Fits Ford 8″ and 9″
See More

Yukon Gear – 8.5" & 8.2" GM carrier installation kit (Part No.57008)

8.5" & 8.2" GM carrier installation kit

from

$109.99
Yukon Carrier Installation Kits are a convenient and low-cost solution for carrier changes in cases where one is upgrading to a positraction limited slip differential, a mechanical locker, or an air operated locker. These kits contain carrier bearings and races and a carrier shim kit.

Product Features:
  • Fits GM 7.5″, 7.625″ 8.2″ and 8.5″
  • Includes carrier bearings and races and “super” carrier shim kit
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USA Standard Gear – Differential Cross Pin (Part No.17011)

Differential Cross Pin

from

$26.99
Spartan spring & pin kit, fits smaller designs.

Product Features:
  • Replacement spring and pin kit for Spartan Locker
  • Fits Dana 30, Dana 44, AMC Model 20, AMC Model 35, and Toyota designs
  • Includes 4 springs and 4 alignment pins
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Yukon Gear – Cover Bolt For Ford 7.5", 8.8" & 9.75" (Part No.33554)

Cover Bolt For Ford 7.5", 8.8" & 9.75"

from

$6.99
Yukon 1541H alloy replacement rear axle for Dana 60, 70, and 80, 35 spline. (40″ to 43.5″) Full float axle (8×3.96″ ). Yukon 1541H alloy axles offer a strength increase over stock while retaining a low cost. Yukon 1541H alloy rear axles come with a one year warranty against manufacturing defects. This is a full-floating axle.

Product Features:
  • 35 spline
  • 8 x 3.96″ bolt pattern
  • Cut to length design fits 40″-43.5″ applications
  • Fits Dana Spicer 60, 70 and 80
See More

Popular 1979 Mercury Cougar Differentials Categories

Most Popular Differential Bearings for 1979 Mercury Cougars

Enhance your 1979 Mercury Cougar with one of the 6 Differential Bearings we have in stock, starting at just $6.99.

National – Bearing Race (Part No.LM102910)

Bearing Race

from

$7.29
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
See More

Yukon Gear – Pilot Bearing retainer for Ford 9" (Part No.33255)

Pilot Bearing retainer for Ford 9"

from

$11.99
Yukon Gear & Axle manufactures a full line of top quality small parts to complete any job including ring gear bolts, crush sleeves, pinion nuts and washers, axle studs, thrust washers and much, much more. For all your differential small parts needs, look no further than Yukon.

Product Features:
  • Pilot bearing retainer for Ford 9″
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Schaeffler – Bearing – TRB (Tapered Roller Bearing) (Part No.KT11)

Bearing - TRB (Tapered Roller Bearing)

from

$15.99
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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Schaeffler – Cup (Part No.M88010)

Cup

from

$10.99
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
See More

National – Bearing Race (Part No.JL69310)

Bearing Race

from

$7.99
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 – Cross Pin Bolt (Part No.33067)

Cross Pin Bolt

from

$6.99
Yukon Gear & Axle manufactures a full line of top quality small parts to complete any job including ring gear bolts, crush sleeves, pinion nuts and washers, axle studs, thrust washers and much, much more. For all your differential small parts needs, look no further than Yukon.

Product Features:
  • Cross pin bolt for Chrysler 8.25″ and 9.25″ rear, Ford 7.5″ and 8.8″, GM 12 bolt car and truck, 8.5″, 8.25″ IFS, 8.0″, 7.625″, 7.5″ and 7.2″ IFS
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Best-Selling 1979 Mercury Cougar Rear Differential Cover Gaskets

Upgrade your Cougar with one of our 5 best-selling Rear Differential Cover Gaskets.

Yukon Gear – 9" Ford Gasket (Part No.23012)

9" Ford Gasket

from

$11.99
9″ Ford gasket.

Product Features:
  • Dropout gasket
  • Fits Ford 9″
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Mr. Gasket – Rear End Gasket – Ford 9" – Blend Of Nitrile Rubber And Fiber For Excellent Sealing And Durability (Part No.82)

Rear End Gasket - Ford 9" - Blend Of Nitrile Rubber And Fiber For Excellent Sealing And Durability

from

$25.99
Mr. Gasket Axle Housing/Differential Cover or Rear End Gaskets are manufactured from a .047 inch thick cellulose/nitrile composite gasket material for excellent sealing and durability. They are precision die-cut for an excellent fit. Fits 1957-1981 Ford 10 bolt 9 inch ring gear.

Product Features:
  • .047″ thick cellulose/nitrile composite gasket material
  • Precision die cut
  • Reusable
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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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Spicer – Performance Differential Gasket – Ford 8.8 Axle (Part No.RD52005)

Performance Differential Gasket - Ford 8.8 Axle

from

$26.99
Spicer performance differential cover gaskets offer all-makes coverage for street, strip, drag, and off-road applications. These gaskets are reusable offering a clean release during replacement. Built with a mechanically and chemically bonder woven steel.

Product Features:
  • Made to adhere without messy RTV sealant This saves on install time by eliminating the time needed for RTV cure.
  • Provides no re-torque design with maximum compression and sealing.
  • Manufactured with proprietary high-density performance material.
  • Made in the USA.
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Victor Reinz – Differential Cover Gasket (Part No.71-14829-00)

Differential Cover Gasket

from

$8.99
Product Features:
  • Choosing Victor Reinz assures getting OE quality parts in gaskets sets that have the coverage, contents, packaging and electronic cataloging to best meet the needs of the aftermarket.
  • Dana engineering-approved for fit, form and function
  • Meets or exceeds OE specifications
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Top-Quality Differential Oil for 1979 Mercury Cougars

Choose a high-quality OEM or aftermarket Differential Oil for Mercury Cougars and enjoy top-notch performance from $44.99.

Yukon Gear – 3 Qt – 80W90 Conventional Gear Oil with Posi Additive (Part No.15003)

3 Qt - 80W90 Conventional Gear Oil with Posi Additive

from

$57.99
Union 76 gear oil is a conventional non-synthetic 80W90 formulation designed for all types of differentials. This kit includes three quarts of oil and a bottle of Yukon Limited Slip Friction modifier that reduces noise and chatter in clutch driven positraction units and limited slip differentials.

Product Features:
  • Includes three quarts of conventional oil and one 4oz bottle of Yukon positraction additive
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Yukon Gear – 3 Qt – Penzoil 80W90 Conventional Gear Oil (Part No.15002)

3 Qt - Penzoil 80W90 Conventional Gear Oil

from

$44.99
Union 76 gear oil is a conventional non-synthetic 80W90 formulation designed for all types of differentials.

Product Features:
  • Includes three quarts of conventional oil
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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 Heavy Shockproof Gear Oil is formulated to provide lasting protection. This kit includes four quarts of oil and a bottle of Yukon Limited Slip Friction modifier that reduces noise and chatter in clutch driven positraction units and limited slip differentials.

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 Heavy Shockproof Gear Oil is formulated to provide lasting protection.

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 Heavy Shockproof Gear Oil is formulated to provide lasting protection.

Product Features:
  • Includes four quarts of Redline Shockproof oil
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Top Picks for 1979 Mercury Cougar Differential Pinion Seals

Invest in one of our 5 durable Differential Pinion Seals for your 1979 Mercury, knowing you’re getting trusted brands and expert craftsmanship.

National – Multi-Purpose Seal (Part No.7044NA)

Multi-Purpose Seal

from

$14.99
National has built a reputation as one of the most respected names in the industry. We have offered premium sealing solutions for more than 75 years. Our design team keeps pace with the industry and provides advanced solutions for today’s vehicles.

Product Features:
  • Design type: spring loaded; multi-lip
  • Temperature range: -40 Deg. F to 225 Deg. F / -40 Deg. C to 107 Deg. C
  • Good low temperature capability
  • Low swell in hydrocarbon fluids
  • Delivers quality and reliable performance for every type of repair
See More

Driveworks – Oil Seal (Part No.S-7044NA)

Oil Seal

from

$6.49
Value-priced seal meets all cataloged application requirements.

Product Features:
  • Brand may vary by location
See More

Yukon Gear – Pinion Seal for ’61-’85 9" Ford (Part No.30137)

Pinion Seal for '61-'85 9" Ford

from

$17.99
Yukon Mighty Seals use the latest design and manufacturing technologies to produce a precision fit that seals tight and lasts for years to come.

Product Features:
  • Pinion seal
  • Fits 1961-1985 Ford 9″
  • 3.00″ O.D.
See More

Schaeffler – Shaft Seal (Part No.SS2934)

Shaft Seal

from

$13.99
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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Motive Gear – Differential Pinion Seal (Part No.7044NA)

Differential Pinion Seal

from

$12.99
Motive Gear offers some of the toughest drive train components on the market today. If you are looking for the largest line of performance ring and pinion gear options available with gear sets in a wide range of ratios for nearly every application, both on and off-road, check out Motive Gear. Motive Gear products can be found in the winner’s circle at racing events worldwide. The superior quality of Motive Gear components is the result of years of racing development, outstanding design and state-of-the-art manufacturing methods. Extensive testing is performed on all products by our in-house engineers.
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Differential Covers for 1979 Mercury Cougars

Make a smart move for your 1979 Mercury Cougar with products all priced from $74.99 to $99.99.

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

Steel Cover for Ford 8.8"

from

$99.99
These Yukon replacement diff covers are a direct bolt-on.

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
These Yukon replacement diff covers take your rig a step beyond the boring factory look. They are the stock OE design finished in chrome.

Product Features:
  • Fits Ford 8.8″
  • Chrome
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Top-Rated Differential Brands For Your 1979 Mercury Cougar

When it comes to finding the perfect Differential for your 1979 Mercury Cougar, Advance Auto Parts has you covered with a wide selection of high-quality OEM and aftermarket options from 16 trusted brands. We carry the most popular Differential brands including Powertrax, Felpro, and National, and more, all known for their exceptional customer ratings (average brand rating of 5.0 stars) and competitive prices, as low as $7.29. Purchasing a Differential from us here at Advance Auto Parts is a smart move for both you and your 1979 Mercury Cougar, providing peace of mind with parts that meet or exceed OEM standards.

Popular Powertrax 1979 Mercury Cougar Differentials

If you’re looking for a top-quality Differential for your 1979 Mercury Cougar, Advance Auto Parts has exactly what you need with our selection of Powertrax Differentials. We have 1 Powertrax Differentials in stock for this fitment, all known for their durability and precision fit. With prices starting at just $551.99, you’ll find the perfect Differential for your needs and budget. Powertrax Differentials for the 1979 Mercury Cougar come highly rated, with over 1 customer reviews and an impressive average rating of 5.0 stars. Choosing a Powertrax Differential from Advance Auto Parts is a smart move to ensure quality and value for your vehicle.
Differential Lock Assembly
from $551.99
(1)
Differential Lock Assembly
“Installed, no issues, works great.”

Top-Quality Felpro 1979 Mercury Cougar Differentials

For those in search of a high-quality Differential for their 1979 Mercury Cougar, Advance Auto Parts offers a great selection of Felpro Differentials. With 1 Felpro 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 $9.99, giving you a range of options to suit your budget. Backed by over 9 customer ratings and an average rating of 4.6 stars, Felpro Differentials provide both reliability and excellent performance. Choosing a Felpro Differential from Advance Auto Parts is a smart investment in your vehicle’s performance and longevity.
Differential Carrier Gasket Oval Shaped 10 Bolt Hole Gasket
from $9.99
(9)
Differential Carrier Gasket Oval Shaped 10 Bolt Hole Gasket
“Right fit the first time.”

FAQs for 1979 Mercury Cougar Differentials

What are the best-selling Differentials for 1979 Mercury Cougars?

Out of 402 Differentials that fit 1979 Mercury Cougars, the following parts are the top sellers:

What’s the price range for 1979 Mercury Cougar Differentials?

The prices of Differentials for the 1979 Mercury Cougar range from $1.99 up to $1,211.99 for the most premium parts.

What is the average price of a Differential for a 1979 Mercury Cougar?

The average price for Differentials for the 1979 Mercury Cougar is $259.42. 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 Cougar model years?

Yes, we carry Differentials for 33 model years of Mercury Cougars between 1967 and 2002. The following model years are the most popular for Differential purchases: 2002, 2001, 2000, 1999, 1997, 1996, 1995, 1994, and 1993.

What are the cheapest Differentials for my 1979 Mercury Cougar?

The cheapest 1979 Mercury Cougar Differentials we carry are:

Does Advance Auto Parts sell Differentials for any other 1979 Mercury models?

Yes. We stock Differentials for 5 other popular 1979 Mercury models. Some of the most popular are 1979 Grand Marquis Differentials, 1979 Capri Differentials, 1979 Zephyr Differentials, 1979 Marquis Differentials, and 1979 Monarch Differentials.

What types of Differentials do you sell for my 1979 Mercury Cougar?

As of 6/2/26, these are some of the most in-demand types of Differentials for a 1979 Mercury Cougar:

Can I get help with 1979 Mercury Cougar 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 Cougar Differentials?

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