1977 Mercury Comet Differentials

Keep Your 1977 Mercury Comet 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 Comet looking sharp and performing at its best. At Advance Auto Parts we carry a wide selection of dependable options, including Differential Ring Gear Bolts, Differential Pinion Seals, and Differential Bearings. 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 Powertrax. For example, National Differentials start at just $12.99 with an average 4.3 star rating. Motive Gear and Powertrax offer similar pricing and quality, backed by strong customer feedback. With over 120 reviews and a solid 5 star average, you can shop with confidence knowing other Mercury Comet owners approve.

Competitive Prices and Extensive Inventory

The average price for a 1977 Mercury Comet Differential at Advance Auto Parts is around $279.85, with a range that starts at $1.99 and goes up to $1,211.99. With 354 options in stock from 12 trusted brands, finding the right fit is easy. Popular picks like Tapered Cone/Cup Wheel Bearing Set, Copper Washer For Ford 9" & 8" Dropout Housing, and Differential Carrier Gasket Oval Shaped 10 Bolt Hole Gasket start at just $5.49 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 1977 Mercury Comet in peak condition, inside and out.

Essential 1977 Mercury Comet Differentials

Yukon Gear – Redline Synthetic "Shock Proof" Oil – 4 Quarts (Part No.15004)

Redline Synthetic "Shock Proof" Oil - 4 Quarts

from

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

Product Features:
  • Includes four quarts of Redline Shockproof oil
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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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National – Multi-Purpose Bearing (Part No.R-1535-TAV)

Multi-Purpose Bearing

from

$41.99
Product Features:
  • PREMIUM MATERIALS: Precision manufactured using premium-grade steel for outstanding durability and performance
  • STRONG AND DURABLE: Controlled heat treatment process for strength and durability
  • 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 – Crush Sleeve (Part No.33093)

Crush Sleeve

from

$10.99
Crush Sleeve for Model 35, Chrysler 7.25″, 8.25″ Ford 8″ & GM 7.75″. Approx 0.495″ long.

Product Features:
  • Crush sleeve for AMC Model 35, Chrysler 7.25″ and 8.25″, Ford 8″ and GM 7.75″
  • 0.495″ tall
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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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Motive Gear – Differential Carrier Gear Kit (Part No.F9-IO28)

Differential Carrier Gear Kit

from

$111.99


Product Features:
  • INT KT 8″ AND 9″ OPEN 28 SPL FRD
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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 – 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″
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Yukon Gear – Pinion Nut (Part No.33154)

Pinion Nut

from

$7.99
Pinion nut for Ford 7.5″, 8″, 8.8″, 9 3/8″ & 9″. 1 1/6″ socket, 3/4″ x 20 thread.

Product Features:
  • Pinion nut for Ford 7.5″, 8″ and 9″
  • 3/4″ x 20 thread
  • 1 1/6″ socket
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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
Product Features:
  • Pinion depth shim kit
  • Fits Ford 9″ with 7/16″ pinion support bolts
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USA Standard Gear – Master Overhaul Kit for the Ford 9" LM501310 Differential (Part No.37035)

Master Overhaul Kit for the Ford 9" LM501310 Differential

from

$213.99
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 LM501310 carrier race
  • Uses Koyo bearings and races
  • Included are carrier bearings and races, pinion bearings and races, pilot bearing, 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 – Pinion Install Kit For Ford Daytona 9" Differential (Part No.13048)

Pinion Install Kit For Ford Daytona 9" Differential

from

$294.99
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 Ford 9″ with Daytona pinion support
  • Included are pinion bearings and races, pinion seal, pinion nut, crush sleeve, complete pinion shim kit, and marking compound with brush.
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Yukon Gear – Pinion Support Bolt For 8" And 9" Ford (Part No.33242)

Pinion Support Bolt For 8" And 9" Ford

from

$6.99
Pinion support bolt for 8″ and 9″ Ford.

Product Features:
  • Pinion support bolt for Ford 8″ and 9″
  • 3/8″ x 24 thread
  • 1.0″ long
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Yukon Gear – Yoke For Ford 9" With 28 Spline Pinion And A 1330 U/Joint Size (Part No.41143)

Yoke For Ford 9" With 28 Spline Pinion And A 1330 U/Joint Size

from

$242.99
Yukon yoke for Ford 9″ with 28 spline pinion and a 1330 U/joint size. 5″ length. 3.625″ snap ring span, 1.125″ cap diameter. Outside snap ring. All Yukon yokes come with a one year warranty against manufacturing defects.

Product Features:
  • Fits Ford 9″
  • 28 spline
  • 1330 u-joint size
  • Outside snap ring design
  • 3.625″ snap ring span
  • 1.125″ cap diameter
  • U-bolt style
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Yukon Gear – Bearing Race Driver (Part No.56019)

Bearing Race Driver

from

$219.99
Bearing race driver. No return.

Product Features:
  • Bearing race driver
  • Fits LM104911 race
  • All steel construction
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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
3.062″ side adjuster, Only Fits Yukon Ford 9″ Drop Out, new design ONLY.

Product Features:
  • Side adjuster
  • Fits Ford 9″
  • 3.062″ designs only
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Motive Gear – Differential Lock Thrust Block (Part No.D3SZ4211A)

Differential Lock Thrust Block

from

$47.49
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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USA Standard Gear – Ring & Pinion Gear Set For Ford 9" In A 4.56 Ratio (Part No.36141)

Ring & Pinion Gear Set For Ford 9" In A 4.56 Ratio

from

$322.99
USA Standard ring & pinion sets are the right choice to add confidence to your install. USA Standard Gear offers a full line of ring & pinion sets for a variety of common & hard to find applications. USA standard gear offers a standard one year warranty against defects on their ring & pinion sets.

Product Features:
  • Fits Ford 9″
  • 9.00″ ring gear diameter
  • 28 spline pinion
  • 10 ring gear bolts
  • 4.56 ratio
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Yukon Gear – 8" & 9" Ford 5-Tab Clutches (Part No.16028)

8" & 9" Ford 5-Tab Clutches

from

$374.99
8″ & 9″ Ford 5-Tab clutches (early Equalock).

Product Features:
  • Clutch kit
  • Fit Ford 9″ Equa Loc positraction
  • 5 outer tabs
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Felpro – Differential Carrier Gasket Oval Shaped 10 Bolt Hole Gasket (Part No.RDS 13270)

Differential Carrier Gasket Oval Shaped 10 Bolt Hole Gasket

from

$5.49
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 and manufactured specifically for the repair environment
  • Unsurpassed quality you can trust
  • Includes all parts needed to complete the repair
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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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FAG US – Shaft Seal (Part No.SS2934)

Shaft Seal

from

$21.79
Our wheel seals are engineered using only the highest-quality materials to meet vehicle manufacturer specificatons. We work with suppliers to design seals that meet FAG’s quality standards. Seals are designed to protect wheel end components from contamination – such as dirt, dust, and moisture – and prevent the loss of grease over the life of the bearing. The specifications for wheel seals are very demanding, and the type required depends on the specific application, position and vehicle class.

Product Features:
  • High-precision and High-quality components used in all KITs
  • Coverage of classic and new high-tech solutions for the best system coverage
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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 – Trac Loc Spring For Ford 9" & 8" (Part No.33518)

Trac Loc Spring For Ford 9" & 8"

from

$8.99
Product Features:
  • Trac Loc spring for Ford 8″ and 9″
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Powertrax – No-Slip Traction System (Part No.9206902800)

No-Slip Traction System

from

$551.99
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 – Pilot Bearing For Ford 8" (Part No.18043)

    Pilot Bearing For Ford 8"

    from

    $40.99
    9.25 Chrysler FRONT PINION KIT , 03 & UP DODGE TRUCK .

    Product Features:
    • Pilot bearing
    • Fits Ford 8″
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    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
    Product Features:
    • Side gear thrust washer for Ford 8″, Ford 9″ and AMC Model 20
    • 0.030″ thick
    See More

    Powertrax – Grip PRO Traction System (Part No.GT108028)

    Grip PRO Traction System

    from

    $537.99
    For vehicles that are driven daily, the Powertrax No-Slip Traction System is the latest design in quiet traction-adding differential technology. It combines the automatic street-friendly smooth operation of a limited-slip differential with the traction performance of a locking differential. The Powertrax No-Slip locker easily installs in to your differential carrier using basic tools and without affecting your ring and pinion settings. Powertrax Grip-Lok, Lock-Right Lockers and No-Slip Traction Systems automatically provide 100% traction on-demand, under the toughest circumstances. The Powertrax Grip-Pro and Grip-LS performance limited slips offer smooth dependable torque transfer and traction for the best of both worlds!
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    Most Popular Differential Ring Gear Bolts for 1977 Mercury Comets

    Enhance your 1977 Mercury Comet with one of the 6 Differential Ring Gear Bolts we have in stock, starting at just $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
    See More

    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
    See More

    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 – 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
    See More

    Best-Selling 1977 Mercury Comet Differential Pinion Seals

    Upgrade your Comet with one of our 3 best-selling Differential Pinion Seals, earning an average 5 stars rating across 2 reviews.

    National – Multi-Purpose Seal (Part No.8181NA)

    Multi-Purpose Seal

    from

    $12.99
    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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    Yukon Gear – 8" Ford Pinion Seal (Part No.30180)

    8" Ford Pinion Seal

    from

    $24.99
    8″ Ford pinion seal.Yukon Mighty seal.

    Product Features:
    • Pinion seal
    • Fits Ford 8″
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    Motive Gear – Differential Pinion Seal (Part No.7044NA)

    Differential Pinion Seal

    from

    $12.99
    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!
    See More

    Top-Quality Differential Bearings for 1977 Mercury Comets

    Choose a high-quality OEM or aftermarket Differential Bearing for Mercury Comets and enjoy top-notch performance from $8.49.

    National – Multi-Purpose Bearing (Part No.A-13)

    Multi-Purpose Bearing

    from

    $13.79
    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

    Driveworks – Tapered Cone/Cup Wheel Bearing Set (Part No.S-A-35)

    Tapered Cone/Cup Wheel Bearing Set

    from

    $26.99
    Value-priced bearing meets all cataloged application requirements.

    Product Features:
    • Brand may vary by location
    See More

    National – Bearing Race (Part No.LM501310)

    Bearing Race

    from

    $8.49
    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
    Pilot bearing retainer for Ford 9″.

    Product Features:
    • Pilot bearing retainer for Ford 9″
    See More

    Yukon Gear – 8" Ford Pilot Bearing Retainer (Part No.33254)

    8" Ford Pilot Bearing Retainer

    from

    $13.99
    8″ Ford pilot bearing retainer.

    Product Features:
    • Pilot bearing retainer for Ford 8″
    See More

    FAG US – Bearing – TRB (Tapered Roller Bearing) (Part No.KT13)

    Bearing - TRB (Tapered Roller Bearing)

    from

    $20.29
    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
    See More

    FAG US – Cup (Part No.LM501310)

    Cup

    from

    $9.99
    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

    Top Picks for 1977 Mercury Comet Differential Oil

    Invest in one of our 3 durable Differential Oil for your 1977 Mercury, knowing you’re getting trusted brands and expert craftsmanship.

    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

    Rear Differential Cover Gaskets for 1977 Mercury Comets

    Make a smart move for your 1977 Mercury Comet with products all priced from $11.99.

    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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    Yukon Gear – 8" Dropout Housing Gasket (Part No.23010)

    8" Dropout Housing Gasket

    from

    $11.99
    8″ dropout housing gasket.

    Product Features:
    • Dropout gasket
    • Fits Ford 8″
    See More

    Top-Rated Differential Brands For Your 1977 Mercury Comet

    When it comes to finding the perfect Differential for your 1977 Mercury Comet, Advance Auto Parts has you covered with a wide selection of high-quality OEM and aftermarket options from 12 trusted brands. We carry the most popular Differential brands including Powertrax, National, and Motive Gear, and more, all known for their exceptional customer ratings (average brand rating of 4.7 stars) and competitive prices, as low as $2.99. Purchasing a Differential from us here at Advance Auto Parts is a smart move for both you and your 1977 Mercury Comet, providing peace of mind with parts that meet or exceed OEM standards.

    Popular Powertrax 1977 Mercury Comet Differentials

    If you’re looking for a top-quality Differential for your 1977 Mercury Comet, 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 Comet come highly rated, with over 1 customer reviews and an impressive average rating of 4.7 stars. Choosing a Powertrax Differential from Advance Auto Parts is a smart move to ensure quality and value for your vehicle.
    No-Slip Traction System
    from $551.99
    (1)
    No-Slip Traction System
    “Installed, no issues, works great.”

    Top-Quality National 1977 Mercury Comet Differentials

    For those in search of a high-quality Differential for their 1977 Mercury Comet, 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 $12.99, with an average price of $21.59, giving you a range of options to suit your budget. Backed by over 20 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.
    Multi-Purpose Bearing
    from $13.79
    (17)
    Multi-Purpose Bearing
    “Good quality product”
    Multi-Purpose Seal
    from $12.99
    (2)
    Multi-Purpose Seal
    “Worked great on this 1966 Mustang w/ 8″ rear end.”
    Shaft Repair Sleeve
    from $37.99
    (1)
    Shaft Repair Sleeve
    “Very delicate piece, but came shipped quite safely and not damaged. High quality.”

    FAQs for 1977 Mercury Comet Differentials

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

    Out of 354 Differentials that fit 1977 Mercury Comets, the following parts are the top sellers:

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

    The prices of Differentials for the 1977 Mercury Comet 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 Comet?

    The average price for Differentials for the 1977 Mercury Comet is $279.85. 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 Comet model years?

    Yes, we carry Differentials for 15 model years of Mercury Comets between 1960 and 1976. The following model years are the most popular for Differential purchases: 1976, 1975, 1974, 1973, 1972, 1971, 1969, 1968, and 1967.

    What are the cheapest Differentials for my 1977 Mercury Comet?

    The cheapest 1977 Mercury Comet 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 Cougar Differentials, 1977 Grand Marquis Differentials, 1977 Capri Differentials, 1977 Marquis Differentials, and 1977 Monarch Differentials.

    What are the top-rated Differentials that fit the 1977 Mercury Comet?

    The one 1977 Mercury Comet Differential we have in stock is the Ring Gear Bolt. It costs $1.99.

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

    As of 11/2/25, these are some of the most in-demand types of Differentials for a 1977 Mercury Comet:

    Can I get help with 1977 Mercury Comet 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 Comet Differentials?

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