1977 Mercury Cougar Differentials

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Keep Your 1977 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 1977 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 Ring Gear Bolts. 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 264 reviews and a solid 4 star average, you can shop with confidence knowing other Mercury Cougar owners approve.

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 1977 Mercury Cougar in peak condition, inside and out.

Essential 1977 Mercury Cougar Differentials

Yukon Gear – Pilot Bearing for Ford 9" (Part No.18042)

Pilot Bearing for Ford 9"

from

$38.99
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
  • Fits Ford 9″
  • 0.656″ thick
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Yukon Gear – Positraction Internals for Ford 8"/9" with 28 Spline Axles, 4-Pinion Design (Part No.16023)

Positraction Internals for Ford 8"/9" with 28 Spline Axles, 4-Pinion Design

from

$315.99
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
  • Fits Ford 9″ with Trac Loc positraction with 28 spline axles
  • Includes two side gears, four pinion gears, cross pin shaft, roll pin and spider gear thrust washers.
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USA Standard Gear – Differential Cross Pin (Part No.17022)

Differential Cross Pin

from

$26.99
9″ Ford Spartan locker cross pin, short.

Product Features:
  • USA Standard Gear heavy-duty cross pin shaft
  • Fits Ford 9″
  • Works with Spartan Locker or standard open spider gears
  • Short shaft for four pinion designs
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Motive Gear – Differential Pinion Bearing Spacer (Part No.SS9)

Differential Pinion Bearing Spacer

from

$45.99
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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Richmond Gear – Differential Pinion Shaft (Part No.CSPF88L)

Differential Pinion 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 limited 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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Yukon Gear – Carrier Bearing Puller Set (Part No.56034)

Carrier Bearing Puller Set

from

$689.99
Yukon Gear & Axle offers a full line of top quality differential tools to save time and money.

Product Features:
  • Not compatible with Dana 70HD, Dana 80, Ford 10.25″ and 10.5″ or GM and Chrysler 11.5″ 1-ton applications
  • Works with an impact gun to safely and easily remove carrier bearings
  • Comes with a handy bench-top stand
  • For 1-ton applications shop Yukon part YT P22
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Yukon Gear – Standard Open Carrier Case – Ford 9" (Part No.20078)

Standard Open Carrier Case - Ford 9"

from

$264.99
9″ standard Open case, bare, 28 & 31 spline, 2 or 4 pinion.

Product Features:
  • Standard open carrier case
  • Fits Ford 9″ with 28 or 31 spline axles
  • Does not include spider gears
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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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Yukon Gear – Trac Loc Spring Plate for Ford 9" & 8 (Part No.33517)

Trac Loc Spring Plate for Ford 9" & 8

from

$10.99
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:
  • Trac Loc spring plate for Ford 8″ and 9″
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Yukon Gear – Grizzly Locker For Ford 8" With 31 Spline Axles (Part No.28007)

Grizzly Locker For Ford 8" With 31 Spline Axles

from

$941.99
The Yukon Grizzly Locker is the ultimate in locking differentials for street, off-road, & drag racing. Grizzly Lockers provide 100% power to both tires, while still allowing for disengagement while negotiating turns. The Yukon Grizzly locker is a mechanical locking differential. It features a forged case and 8620 internals for maximum strength. It’s patented design reduces common locker failures. All units assembled in the USA! All Grizzly Lockers are backed by the best warranty in the business! Yukon covers the replacement unit and covers any collaterally damaged parts and associated labor, up to $2,000!

Product Features:
  • Fits Ford 8″ with 31 spline axles
  • Patented internal design reduces common locker failures
  • 8620 internals for added strength
  • Assembled in the USA
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Valvoline – High Performance Transmission & Differential Gear Oil: Conventional 75W-90, 1 Quart (Part No.VV820)

High Performance Transmission & Differential Gear Oil: Conventional 75W-90, 1 Quart

from

$12.99
Valvoline High Performance Synthetic Gear Oil is the thermally stabile extreme pressure lubricant that offers outstanding protection for gearboxes and differentials in passenger cars, light trucks, and sport utility vehicles. Combined with high quality synthetic base oils, our formula’s superior additives help reliably safeguard against severe temperatures, shock loads, foaming, scuffing, scouring, corrosion and pitting in high load, high torque and high horsepower conditions. Can be used in conventional and limited slip hypoid differentials where GL-5 is specified as well as non-synchronized manual transmissions that require GL-4. Protect your gears with Valvoline, the #1 gear oil brand.

Product Features:
  • HIGH PERFORMANCE EXTREME-PRESSURE ADDITIVES HELP MINIMIZE WEAR in high pressure and high temperature conditions
  • EXCEPTIONAL HIGH AND LOW TEMPERATURE PROTECTION can easily handle both winter and summer conditions for dependable coverage and protection year-round
  • 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
  • SUPERIOR ADDITIVES help reliably safeguard against severe temperatures, shock loads, foaming, scuffing, scouring, corrosion and pitting in high load, high torque and high horsepower conditions
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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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Yukon Gear – Silver Aluminum Pinion Support for 9" Ford Daytona (Part No.32037)

Silver Aluminum Pinion Support for 9" Ford Daytona

from

$269.99
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:
  • 6061 aluminum
  • Larger inner pinion bearing reduces gear deflection under high load
  • Fits Ford 9″ with 28 spline pinion
  • 6061 aluminum
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Richmond Gear – RngPnn (Part No.69-0379-1)

RngPnn

from

$577.99
RngPnn

Yukon Gear – Dana 44, Ford 8" / 9", and Model 20 Side Gear Thrust Washer Replacement (Part No.33283)

Dana 44, Ford 8" / 9", and Model 20 Side Gear Thrust Washer Replacement

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:
  • Side gear thrust washer for Ford 8″, Ford 9″ and AMC Model 20
  • 0.030″ thick
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Yukon Gear – O-ring for 9" Ford (Part No.30028)

O-ring for 9" Ford

from

$14.99
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 support O-ring
  • Fits Ford 9″
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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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Yukon Gear – Trac Loc Clutch Guide for 9" Ford (Part No.33250)

Trac Loc Clutch Guide for 9" Ford

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:
  • Clutch guide
  • Fits Ford 8″ and 9″
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Richmond Gear – Differential Spool (Part No.81-0935-3)

Differential Spool

from

$259.99
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.
See More

Yukon Gear – Pinion Nut (Part No.33154)

Pinion Nut

from

$7.99
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 for Ford 7.5″, 8″ and 9″
  • 3/4″ x 20 thread
  • 1 1/6″ socket
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USA Standard Gear – Differential Rebuild Kit (Part No.37028)

Differential Rebuild Kit

from

$275.99
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 8″
  • 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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Yukon Gear – Trac-Loc For Ford 8" Wtih 28 Spline Axles – Street Design (Part No.26002)

Trac-Loc For Ford 8" Wtih 28 Spline Axles - Street Design

from

$889.99
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 8″ with 28 spline axles
  • Trac Loc positraction
  • Clutch style positraction
  • Street 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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Dorman – Differential Pinion Yoke Assembly (Part No.697-527)

Differential Pinion Yoke Assembly

from

$177.99
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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Motive Gear – Differential Gear Install Kit (Part No.F8IK)

Differential Gear Install Kit

from

$44.49
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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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
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 Ford 7.5″, 8.8″ and some 9.75″
  • 2.785″ O.D.
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Yukon Gear – Pinion Install Kit for Ford 9" Differential (Part No.13042)

Pinion Install Kit for Ford 9" Differential

from

$175.99
Yukon Pinion Installation Kits are a terrific solution for gear installation on lower mileage vehicles where the carrier bearings and races can be reused. This kit features Timken bearings and races along with high-quality seals and small parts. Yukon does extensive research for each application to make sure your kit will arrive with all the correct parts you need to install your gear set.

Product Features:
  • Fits Ford 9″ without aftermarket Daytona pinion support
  • Included are pinion bearings and races, pinion seal, pilot bearing , crush sleeve , complete pinion shim kit, and marking compound with brush.
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Yukon Gear – Ford 8" & 9" Tracloc Ring Gear Bolt (Part No.33044)

Ford 8" & 9" Tracloc Ring Gear Bolt

from

$4.99
Ford 8″ & 9″ TracLoc ring gear bolt, 1-1/4″ long.

Product Features:
  • Ring gear bolt for Ford 8″ and 9″
  • For use with Trac Loc limited slip
  • 1.25″ long
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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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Most Popular Differential Bearings for 1977 Mercury Cougars

Enhance your 1977 Mercury Cougar with one of the 5 Differential Bearings we have in stock, starting at just $7.29.

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
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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
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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
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Best-Selling 1977 Mercury Cougar Rear Differential Cover Gaskets

Upgrade your Cougar with one of our 3 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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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
See More

Top-Quality Differential Ring Gear Bolts for 1977 Mercury Cougars

Choose a high-quality OEM or aftermarket Differential Ring Gear Bolt for Mercury Cougars and enjoy top-notch performance from $1.99.

Yukon Gear – Ford 8" & 9" Standard Open, Ag, & Detroit Locker Ring Gear Bolt (Part No.33058)

Ford 8" & 9" Standard Open, Ag, & Detroit Locker Ring Gear Bolt

from

$5.99
Ford 8″ & 9″ standard Open, AG, & Detroit locker ring gear bolt. 7/16″ head, .925″ long.

Product Features:
  • Ring gear bolt for Ford 8″ and 9″
  • For use with standard open carrier, Auburn Gear limited slip and Detroit Locker
  • 7/16″ head
  • .925″ long
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Yukon Gear – Ford 8" & 9" Standard Open, Ag, & Detroit Locker Ring Gear Bolt (Part No.33043)

Ford 8" & 9" Standard Open, Ag, & Detroit Locker Ring Gear Bolt

from

$5.99
Ford 8″ & 9″ standard Open, AG, & Detroit locker ring gear bolt, 1.0″ long, Ford.

Product Features:
  • Ring gear bolt for Ford 8″ and 9″
  • For use with standard open carrier, Auburn Gear limited slip and Detroit Locker
  • 1.0″ long
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Yukon Gear – Ford 8" & 9" Tracloc Ring Gear Bolt (Part No.33044)

Ford 8" & 9" Tracloc Ring Gear Bolt

from

$4.99
Ford 8″ & 9″ TracLoc ring gear bolt, 1-1/4″ long.

Product Features:
  • Ring gear bolt for Ford 8″ and 9″
  • For use with Trac Loc limited slip
  • 1.25″ long
See More

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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ARP Auto Racing – For Use With Ford 9" Using 5/8"Socket, 0.94"L Under Head, 7/16"-20, 12Point Head (Part No.250-3002)

For Use With Ford 9" Using 5/8"Socket, 0.94"L Under Head, 7/16"-20, 12Point Head

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
  • 0.95″ Underhead Length
  • 200,000 PSI
  • Sold As A Set
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Yukon Gear – 9" Ford Standard Open & Detroit Locker Ring Gear Bolt For Safety Wire (Part No.33055)

9" Ford Standard Open & Detroit Locker Ring Gear Bolt For Safety Wire

from

$14.99
9″ Ford standard Open & Detroit locker ring gear bolt for Safety wire. 12 point 5/8″ head, .950″ long.

Product Features:
  • Ring gear bolt for Ford 8″ and 9″
  • For use with standard open carrier, Auburn Gear limited slip and Detroit Locker
  • Safety wire design
  • 12 point 5/8″ head
  • .950″ long
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Yukon Gear – Trac Loc Ring Gear Bolt Washer For 8" And 9" Ford (Part No.33245)

Trac Loc Ring Gear Bolt Washer For 8" And 9" Ford

from

$3.99
Trac Loc ring gear bolt washer for 8″ and 9″ Ford.

Product Features:
  • Ring gear bolt for Ford 8″ and 9″
  • For Trac Loc positraction applications only
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Top Picks for 1977 Mercury Cougar Differential Pinion Seals

Invest in one of our 6 durable Differential Pinion Seals for your 1977 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
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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
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Driveworks – Oil Seal (Part No.S-51098)

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

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$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 Oil for 1977 Mercury Cougars

Make a smart move for your 1977 Mercury Cougar with products all priced from $44.99 to $148.99.

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

3 Qt - 80W90 Conventional Gear Oil with Posi Additive

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$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-Rated Differential Brands For Your 1977 Mercury Cougar

When it comes to finding the perfect Differential for your 1977 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 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 1977 Mercury Cougar, providing peace of mind with parts that meet or exceed OEM standards.

Popular Powertrax 1977 Mercury Cougar Differentials

If you’re looking for a top-quality Differential for your 1977 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 1977 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 1977 Mercury Cougar Differentials

For those in search of a high-quality Differential for their 1977 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 1977 Mercury Cougar Differentials

What are the best-selling Differentials for 1977 Mercury Cougars?

Out of 309 Differentials that fit 1977 Mercury Cougars, the following parts are the top sellers:

What’s the price range for 1977 Mercury Cougar Differentials?

The prices of Differentials for the 1977 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 1977 Mercury Cougar?

The average price for Differentials for the 1977 Mercury Cougar is $255.60. 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 1977 Mercury Cougar?

The cheapest 1977 Mercury Cougar Differentials we carry are:

Does Advance Auto Parts sell Differentials for any other 1977 Mercury models?

Yes. We stock Differentials for 5 other popular 1977 Mercury models. Some of the most popular are 1977 Grand Marquis Differentials, 1977 Capri Differentials, 1977 Marquis Differentials, 1977 Comet Differentials, and 1977 Monarch Differentials.

What types of Differentials do you sell for my 1977 Mercury Cougar?

As of 6/2/26, these are some of the most in-demand types of Differentials for a 1977 Mercury Cougar:

Can I get help with 1977 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.