1991 Mercury Cougar Differentials

Keep Your 1991 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 1991 Mercury Cougar looking sharp and performing at its best. At Advance Auto Parts we carry a wide selection of dependable options, including Rear Differential Cover Gaskets, Rear Housing Cover Gaskets, and Differential Covers. 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, Motive Gear, and Valvoline. For example, National Differentials start at just $7.99 with an average 4.3 star rating. Motive Gear and Valvoline offer similar pricing and quality, backed by strong customer feedback. With over 1,635 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 1991 Mercury Cougar Differential at Advance Auto Parts is around $196.26, with a range that starts at $1.29 and goes up to $1,115.99. With 159 options in stock from 15 trusted brands, finding the right fit is easy. Popular picks like High Performance 5W-30 Synthetic Engine Oil, Better Wear Protection, 5 Quart, DEX/MERC ATF Conventional Automatic Transmission Fluid, 1 Quart, and Differential Shaft Lock Bolt start at just $6.79 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 1991 Mercury Cougar in peak condition, inside and out.

Essential 1991 Mercury Cougar Differentials

Richmond Gear – MiniSpool (Part No.78-8831-1)

MiniSpool

from

$151.99
MiniSpool

USA Standard Gear – Standard Spider Gear Set For Ford 9", 31 Spline, 4-Pinion Design (Part No.39018)

Standard Spider Gear Set For Ford 9", 31 Spline, 4-Pinion Design

from

$249.99
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 – 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″
See More

Yukon Gear – Dura Grip Positraction For Ford 8.8" With 28 Spline Axles (Part No.26005)

Dura Grip Positraction For Ford 8.8" With 28 Spline Axles

from

$834.99
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 Dura Grip uses a nodular case and forged 4320 internals for added strength along with composite clutches for high performance and long life. All units are Rebuildable and many offer upgrades to increase aggressiveness for racing applications. Each unit carries a one year warranty against defects.

Product Features:
  • Fits Ford 8.8″ with 28 spline axles
  • 4-spring, clutch style positraction
  • 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 – Crush Sleeve Eliminator Kit For Ford 9" (Part No.55041)

Crush Sleeve Eliminator Kit For Ford 9"

from

$68.99
9″ Ford 2 piece solid preload pinion spacer, Daytona or standard.

Product Features:
  • Crush sleeve eliminator kit for Ford 9″ with 28 spline pinion
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Motive Gear – Differential Pinion Nut (Part No.379570S)

Differential Pinion Nut

from

$6.99
All Motive Gear products are engineered for their specific application and manufactured in state of the art facilities. All of our products undergo rigid quality control processes to insure proper fit, performance and longevity. Motive Gear products can be found in the winners circle at NHRA, IHRA, NMRA, NMCA, SODA, SCORE, BITD, Ultra-4 and NASCAR events because we offer unmatched selection and quality demanded by racers and their crew chiefs – the same quality and selection demanded by DIY customers and top mechanics. With four warehouses strategically located across North America, most Motive Gear orders arrive within 2-4 days. Win with Motive Gear!
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Dorman – Differential Clutch Kit (Part No.697-780)

Differential Clutch Kit

from

$262.99
This differential disc kit is a low-cost, time-saving repair solution for the posi-traction function. They are designed to match the fit and performance of the original disc on specific vehicle years, makes and models.

Product Features:
  • Direct replacement – this differential clutch kit provides the necessary components for repairing the original equipment on specific vehicles
  • Quality materials – all components are built for reliable longevity and performance
  • Smart solution – provides original equipment fit and function for a competitive price compared to original manufacturer
  • Trustworthy quality – backed by team of designers and engineers in the United States
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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
See More

Pro-King – Differential Case (Empty) (Part No.762B714A)

Differential Case (Empty)

from

$242.99
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.
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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ARP Auto Racing – For Use With Ford 8.8 And 9" Using 3/4"Socket, 0.75"L Under Head, 7/16"-20 (Part No.250-3003)

For Use With Ford 8.8 And 9" Using 3/4"Socket, 0.75"L Under Head, 7/16"-20

from

$43.99
The tremendous shock loads generated at launch by most any drag racing vehicle equipped with today sticky tire compounds or the acceleration and deceleration of oval track cars put considerable strain on the ring gear. For this reason, the fastener experts at ARP have developed the Pro Series ring gear bolts. they are forged from premium grade 8740 chrome moly steel and are heat treated to a nominal rating of 200,000 PSI tensile strength. Specially hardened, precision ground washers are included where required. Available to fit most any ring gear setup ranging from popular 9 Inch Ford GM 10 and 12 bolt rear ends to the beefy strange differentials found in top fuel and funny car applications.

Product Features:
  • Forged From Premium Grade 8740 Chrome Moly Steel
  • Heat Treated
  • Nominally Rated At 200,000 Psi Tensile Strength
  • Specially Hardened, Precision Ground Washers
  • 0.75″ Underhead Length
  • 200,000 PSI
  • Sold As A Set
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Yukon Gear – The Carrier Bearing Puller (Part No.56072)

The Carrier Bearing Puller

from

$883.99
The Yukon carrier bearing Puller works with an impact gun to quickly and safely remove carrier bearings without damaging them. This unit comes with a handy bench top stand and works with up to one ton applications including Dana 70HD, Dana 80, 10.25″ & 10.5″ Ford, or GM & Chrysler 11.5″ differentials.

Product Features:
  • Carrier bearing puller
  • Works with an impact gun to safely and easliy remove carrrier bearings
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Yukon Gear – Shim Kit For 9" Ford Tracloc Clutch (Part No.16030)

Shim Kit For 9" Ford Tracloc Clutch

from

$46.99
Shim kit for 9″ Ford TracLoc clutch, (8″ also) positraction.

Product Features:
  • Shim kit
  • Fits Ford 8″ and 9″ Trac Loc
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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
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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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Motive Gear – Differential Ring and Pinion (Part No.F7.5-308)

Differential Ring and Pinion

from

$238.99


Product Features:
  • FRD 10BL 7.5 R/P 3.08 MG
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Dorman – Differential Pinion Yoke Assembly (Part No.697-530)

Differential Pinion Yoke Assembly

from

$137.99
Worn or damaged differential end yoke causing driveline vibrations? This direct replacement end yoke matches the original equipment part for a trustworthy repair and reliable performance.

Product Features:
  • Direct replacement – this differential end yoke matches the fit and construction of the original yoke
  • Excellent value – this replacement end yoke offers original equipment quality at a fraction of the price of dealer parts
  • Quality materials – this end yoke is machined from cast iron for strength and is precision machined for reliability
  • Validated fit – this differential end yoke has been tested to confirm accurate fit
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Felpro – Axle Housing Cover Gasket Oval Shaped 10 Bolt Hole Gasket (Part No.RDS 55393)

Axle Housing Cover Gasket Oval Shaped 10 Bolt Hole Gasket

from

$7.49
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
See More

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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Pro-King – Differential Internal Nest Kit (Part No.762B717)

Differential Internal Nest Kit

from

$239.99
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.
See More

Yukon Gear – Standard Open Side Gear And Thrust Washer For 7.5" Ford (Part No.33295)

Standard Open Side Gear And Thrust Washer For 7.5" Ford

from

$19.99
Standard Open side gear thrust washer for 7.5″ Ford.

Product Features:
  • Side gear thrust washer
  • Fits Ford 7.5″
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Richmond Gear – Differential Cross Shaft (Part No.CSPF88L)

Differential Cross Shaft

from

$26.99
Richmond Gear is the leading manufacturer of professional quality, high-performance drivetrain products. Our complete line of products ranges from high performance ring-and-pinion sets for serious street and racing applications to torque-hungry manual transmissions and components. Richmond Gear products have been winners both at the Daytona 500 and U.S. Nationals for decades. WINNERS RUN RICHMOND!

Product Features:
  • For over 80-years, the Richmond Double-Diamond logo has represented some of the highest quality gears in the racing industry. Winners Run Richmond!
  • The superior quality of Richmond gearsets is a result of outstanding design, world class manufacturing and an extensive testing process that is performed on all products.
  • Richmond performance gearsets have been winners for decades at: NHRA, NMRA, NMCA, Daytona 500, WISSOTA and U.S. Nationals.
  • Richmond Gear is a leading manufacturer of high performance ring and pinion gearsets and drivetrain components, backed by a two year warranty.
  • Engineered to perform faster and be more reliable, Richmond performance drivetrain products are the result of a continuous research and development program combined with state-of-the-art manufacturing capabilities.
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USA Standard Gear – Master Overhaul Kit for the Ford 9" LM603011 Differential (Part No.37036)

Master Overhaul Kit for the Ford 9" LM603011 Differential

from

$226.99
USA Standard Master Overhaul kits let you finish your install with confidence. This kit uses Koyo bearings and races. Included are carrier bearings and races, pinion bearings and races, pinion seal, complete shim kit, ring gear bolts, pinion nut, crush sleeve (if applicable), oil baffles and slingers (if applicable), threading locking compound, marking compound with brush and gasket.

Product Features:
  • Fits Ford 9″ with LM603011 carrier races
  • Uses Koyo bearings and races
  • Included are carrier bearings and races, pinion bearings and races, pinion seal, complete shim kit, ring gear bolts, pinion nut, crush sleeve, thread locker, marking compound with brush and gasket.
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Motive Gear – Differential Gear Install Kit (Part No.F9IK)

Differential Gear Install Kit

from

$33.99
Product Features:
  • MINI INSTALL KIT FORD 9″
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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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National – Shaft Repair Sleeve (Part No.99199)

Shaft Repair Sleeve

from

$37.99
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:
  • Designed to repair damaged, grooved or worn shafts
  • Durable stainless steel construction for corrosion-free sealing surface that surpasses most original shaft specifications
  • Ideal for a shaft where indications of seal wear, such as tracks or grooves have developed
  • Ultra-thin construction (0.01/0.25mm wall thickness) allows original seal size to be used with minimal additional lip loading
  • Easy to install with removable flange and installation tool
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Powertrax – No-Slip Traction System (Part No.9206883108)

No-Slip Traction System

from

$544.99
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!The Powertrax® Lock-Right Locker provides outstanding traction for off-road machines and race vehicles. Powertrax No-Slip Traction Systems deliver excellent performance to street-driven cars and trucks.
  • Powertrax® lockers range from the original, Lock-Right for serious straight-line performance, to the No-Slip traction system for street-able vehicles.
  • Powertrax® 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.
  • Powertrax® = Extreme Traction Systems!
  • See More

    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
    Pinion gear thrust washer for 8″ and 9″ Ford, Model 20, and 7.25″ Chrysler.

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

    Most Popular Rear Differential Cover Gaskets for 1991 Mercury Cougars

    Enhance your 1991 Mercury Cougar with one of the 3 Rear Differential Cover Gaskets we have in stock, starting at just $4.99.

    Felpro – Axle Housing Cover Gasket Round Shaped 10 Bolt Hole Gasket (Part No.RDS 55460)

    Axle Housing Cover Gasket Round Shaped 10 Bolt Hole Gasket

    from

    $8.99
    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
    See More

    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″
    See More

    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.
    See More

    Best-Selling 1991 Mercury Cougar Rear Housing Cover Gasket

    Upgrade your Cougar with our best-selling Rear Housing Cover Gasket.

    Felpro – Axle Housing Cover Gasket Round Shaped 10 Bolt Hole Gasket (Part No.RDS 55459)

    Axle Housing Cover Gasket Round Shaped 10 Bolt Hole Gasket

    from

    $9.99
    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
    • Unsurpassed quality you can trust
    • Validated for fit, form and function
    • Each Fel-Pro gasket, no matter how small, is engineered to exacting standards with proprietary design, engineering and manufacturing processes
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    Top-Quality Differential Covers for 1991 Mercury Cougars

    Choose a high-quality OEM or aftermarket Differential Cover for Mercury Cougars and enjoy top-notch performance from $99.99.

    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
    See More

    Yukon Gear – DiffrlCover (Part No.32364)

    DiffrlCover

    from

    $99.99
    DiffrlCover

    Top Picks for 1991 Mercury Cougar Differential Oil

    Invest in one of our 6 durable Differential Oil for your 1991 Mercury, knowing you’re getting trusted brands and expert craftsmanship.

    Royal Purple – High Performance 5W-30 Synthetic Engine Oil, Better Wear Protection, 5 Quart (Part No.51530)

    High Performance 5W-30 Synthetic Engine Oil, Better Wear Protection, 5 Quart

    from

    $41.99
    Royal Purple Motor Oil is a specially formulated multi viscocity oil for use in gasoline and diesel engines of all types from cars and trucks to SUVs, motorcycles and boats. Royal Purple(R) Motor Oil with Synerlec(R) additive technology reduces friction, which results in a 1-3 percent increase in horsepower, lowers operating temperatures, provides superior corrosion protection, improves fuel economy, reduces emissions and extends oil life. A.P.I. Certified.

    Product Features:
    • Better wear protection
    • Increased fuel efficiency
    • Better protection of the expensive catalytic emission system
    • Improved compatibility with fuels containing ethanol
    • Superior corrosion protection
    • Meets ILSAC GF-5 and Dexos1 performance requirements
    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
    See More

    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

    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
    See More

    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
    See More

    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
    See More

    Top-Rated Differential Bearings for 1991 Mercury Cougars

    Make a smart move for your 1991 Mercury Cougar 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
    See More

    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
    See More

    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
    See More

    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 1991 Mercury Cougar

    When it comes to finding the perfect Differential for your 1991 Mercury Cougar, Advance Auto Parts has you covered with a wide selection of high-quality OEM and aftermarket options from 15 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 $7.99. Purchasing a Differential from us here at Advance Auto Parts is a smart move for both you and your 1991 Mercury Cougar, providing peace of mind with parts that meet or exceed OEM standards.

    Popular Valvoline 1991 Mercury Cougar Differentials

    If you’re looking for a top-quality Differential for your 1991 Mercury Cougar, Advance Auto Parts has exactly what you need with our selection of Valvoline Differentials. We have 1 Valvoline Differentials in stock for this fitment, all known for their durability and precision fit. With prices starting at just $69.99, you’ll find the perfect Differential for your needs and budget. Valvoline Differentials for the 1991 Mercury Cougar come highly rated, with over 364 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.

    Top-Quality National 1991 Mercury Cougar Differentials

    For those in search of a high-quality Differential for their 1991 Mercury Cougar, 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 $18.42, giving you a range of options to suit your budget. Backed by over 7 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.
    Shaft Repair Sleeve
    from $37.99
    (1)
    Shaft Repair Sleeve
    “Very delicate piece, but came shipped quite safely and not damaged. High quality.”
    Bearing Race
    from $9.29
    (2)
    Bearing Race
    “Reasonable price and woks well. front diff 2006 Escalade esv”
    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 1991 Mercury Cougar Differentials

    What are the best-selling Differentials for 1991 Mercury Cougars?

    Out of 159 Differentials that fit 1991 Mercury Cougars, the following parts are the top sellers:

    What’s the price range for 1991 Mercury Cougar Differentials?

    The prices of Differentials for the 1991 Mercury Cougar range from $1.29 up to $1,115.99 for the most premium parts.

    What is the average price of a Differential for a 1991 Mercury Cougar?

    The average price for Differentials for the 1991 Mercury Cougar is $196.26. 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 1991 Mercury Cougar?

    The cheapest 1991 Mercury Cougar Differentials we carry are:

    Does Advance Auto Parts sell Differentials for any other 1991 Mercury models?

    Yes. We stock Differentials for 5 other popular 1991 Mercury models. Some of the most popular are 1991 Grand Marquis Differentials, 1991 Colony Park Differentials, 1991 Capri Differentials, 1991 Tracer Differentials, and 1991 Topaz Differentials.

    What are the top-rated Differentials that fit the 1991 Mercury Cougar?

    Based on 1,635 reviews by customers, our 1991 Mercury Cougar Differentials have an average customer rating of 4 stars. These are the highest-rated categories of Differentials for the 1991 Mercury Cougar and their top-rated products:

    What types of Differentials do you sell for my 1991 Mercury Cougar?

    As of 11/2/25, these are some of the most in-demand types of Differentials for a 1991 Mercury Cougar:

    Can I get help with 1991 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.