1991 Mercury Grand Marquis Differentials

Keep Your 1991 Mercury Grand Marquis 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 Grand Marquis looking sharp and performing at its best. At Advance Auto Parts we carry a wide selection of dependable options, including Rear Housing Cover Gaskets, Rear Differential 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 FELPRO. For example, National Differentials start at just $7.99 with an average 4.3 star rating. Motive Gear and FELPRO offer similar pricing and quality, backed by strong customer feedback. With over 667 reviews and a solid 4 star average, you can shop with confidence knowing other Mercury Grand Marquis owners approve.

Competitive Prices and Extensive Inventory

The average price for a 1991 Mercury Grand Marquis Differential at Advance Auto Parts is around $283.49, with a range that starts at $1.29 and goes up to $2,064.99. With 224 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 Axle Housing Cover Gasket Rectangular Shaped, 10 Bolt Hole Gasket start at just $11.99 and offer a great balance of form and function.

Explore Related Parts

While you’re upgrading or replacing your Differential, don’t forget to check out other key components like Drive Shafts and Axles and Universal Joints. At Advance Auto Parts, we’re here to help you keep your 1991 Mercury Grand Marquis in peak condition, inside and out.

Essential 1991 Mercury Grand Marquis Differentials

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
See More

Yukon Gear – Side Gear And Thrust Washer (0.875" Shaft) For 8.8" Ford (Part No.33300)

Side Gear And Thrust Washer (0.875" Shaft) For 8.8" Ford

from

$11.99
Side gear thrust washer (0.875″ shaft) for 8.8″ Ford.

Product Features:
  • Side gear thrust washer for Ford 8.8″
  • 0.875″ diameter cross pin shaft applications only
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Yukon Gear – Super Carrier Shim Kit For Ford 8.8", GM 12 Bolt Car & Truck, 8.6 & Vette (Part No.55002)

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

from

$59.99
Product Features:
  • Super carrier shim kit for Ford 8.8″, GM 12 bolt passenger car and truck, GM 8.0″, 8.6″, 8.6″ IRS and 1963-1979 Corvette
  • Interlocking design makes installation much easier
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Yukon Gear – Carrier Installation Kit For Ford 8.8" Differential (Part No.57007)

Carrier Installation Kit For Ford 8.8" Differential

from

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

Product Features:
  • Fits Ford 8.8″
  • Includes carrier bearings and races and “super” carrier shim kit
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Yukon Gear – Trac Loc For Ford 9" Wtih 28 Spline Axles – Aggressive Design (Part No.26007)

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

from

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

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

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

from

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

Product Features:
  • Outer oil slinger for Ford 10.25″, 7.5″, 8.8″ and 9″ also Jeep JK and Nissan Titan rear
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Richmond Gear – MiniSpool (Part No.78-8831-1)

MiniSpool

from

$151.99
MiniSpool

Yukon Gear – Trao Loc Spring For Ford 8.8", 31 Spline (Part No.33516)

Trao Loc Spring For Ford 8.8", 31 Spline

from

$99.99
Product Features:
  • Trac Loc spring for Ford 8.8″
  • 31 spline applications only
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Yukon Gear – 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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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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Motive Gear – Differential Gear Install Kit (Part No.F9IKN)

Differential Gear Install Kit

from

$46.49
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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Powertrax – Lock Right Locker (Part No.1821-LR)

Lock Right Locker

from

$441.99
The Powertrax Lock-Right ultra-strength alloy locker’s straight-line performance is equal to a solid spool, but automatically unlocks in turns. Best suited for extreme off-road to severe on-road use, Powertrax Lock Right lockers replace the spider gears in your open differential carrier using basic tools and without affecting your ring and pinion settings. The whole job can be done in your driveway in a couple of hours, pin included! 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

    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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    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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    Yukon Gear – 8.8" Ford 3/4" Notched Cross Pin Shaft (0.750", ’85 And Older) (Part No.33432)

    8.8" Ford 3/4" Notched Cross Pin Shaft (0.750", '85 And Older)

    from

    $78.99
    8.8″ Ford 3/4″ Notched cross pin shaft (0.750″, ’85 and older). This cross pin shaft is not compatible with Powertrax Lock Rights or Spartan Lockers.

    Product Features:
    • Cross pin shaft
    • Fits Ford 8.8″
    • 0.750″ diameter
    • Notched
    • Not compatible with Spartan Lockers or Lock Rights
    See More

    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
    See More

    Pro-King – Differential Cross Shaft (Part No.742G930)

    Differential Cross Shaft

    from

    $2.99
    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 – Bearing Race Driver (Part No.56023)

    Bearing Race Driver

    from

    $219.99
    Bearing race driver. No return.

    Product Features:
    • Bearing race driver
    • Fits M88010 race
    • All steel construction
    See More

    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.
    See More

    Yukon Gear – Steel Spool For Ford 9" With 35 Spline Axles, Small Bearing (Part No.32098)

    Steel Spool For Ford 9" With 35 Spline Axles, Small Bearing

    from

    $404.99
    Yukon Performance steel spool for 9″ Ford with 35 spline axles. Spool uses 1.785″ journal bearings. fits 2.8″ and 3.0″ cases. Yukon performance spools are made from the highest quality materials to ensure high strength and long life in performance applications. Spools provide 100% power to both tires at all times and are a lower cost alternative to lockers. Spools are not recommended for street driven vehicles. Yukon Performance spools come with a one year warranty against manufacturing defects.

    Product Features:
    • Fits Ford 9″ with 35 spline axles
    • Small bearing journal to fit 2.968″ and 3.062″ dropouts
    • Provides 100% traction to both wheels at all times
    • Not recommended for street driven vehicles
    See More

    Yukon Gear – 18 Plate Steel Clutches For GM 8.2", GM 8.5", 12T, 12P, Ford 8.8" & Cast Iron ‘Vette (Part No.16110)

    18 Plate Steel Clutches For GM 8.2", GM 8.5", 12T, 12P, Ford 8.8" & Cast Iron 'Vette

    from

    $483.99
    Product Features:
    • Clutch kit
    • Fits Ford 8.8″, 1963-1979 Corvette, GM 12 bolt passenger car and truck, 8.2″, 8.5″ and 8.6″ Dura Grip positraction
    • 18 piece kit
    • Steel clutches
    See More

    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
    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

    Pro-King – Differential Pinion Shim Kit (Part No.742G200A)

    Differential Pinion Shim Kit

    from

    $18.49
    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 – 8.8" Ford Low Profile Ta HD Aluminum Rear Cover (Part No.32114)

    8.8" Ford Low Profile Ta HD Aluminum Rear Cover

    from

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

    Product Features:
    • Fits Ford 8.8″
    • Aluminum girdle cover
    See More

    Motive Gear – Differential Ring and Pinion (Part No.F9-486A)

    Differential Ring and Pinion

    from

    $199.99


    Product Features:
    • FRD 10BLT 9.0 R/P 4.86A MG
    See More

    Yukon Gear – Trac Loc Case For Ford 9" (Part No.20079)

    Trac Loc Case For Ford 9"

    from

    $339.99
    9″ TracLoc case, bare, 28 & 31 spline, 2or4 PIN, 4 TAB clutches.

    Product Features:
    • Trac Loc positraction carrier case
    • Does not include spider gears
    • Fits Ford 9″ with 28 or 31 spline axles
    See More

    Yukon Gear – Standard Open Carrier Case, Ford 8.8", 28 Spline (Part No.20076)

    Standard Open Carrier Case, Ford 8.8", 28 Spline

    from

    $379.99
    8.8″ 28 spline standard Open bare case (incl REVERSE) 3/4″ cross pin Hole.

    Product Features:
    • Standard open carrier case
    • Does not include spider gears
    • Fits Ford 8.8″ with 28 spline axles
    • 3/4″ cross pin bore
    See More

    Most Popular Rear Housing Cover Gasket for 1991 Mercury Grand Marquis

    Enhance your 1991 Mercury Grand Marquis with this popular Rear Housing Cover Gasket we have in stock, for $14.99.

    Felpro – Axle Housing Cover Gasket Oval Shaped 10 Bolt Hole Gasket (Part No.RDS 55081)

    Axle Housing Cover Gasket Oval Shaped 10 Bolt Hole Gasket

    from

    $14.99
    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

    Best-Selling 1991 Mercury Grand Marquis Rear Differential Cover Gaskets

    Upgrade your Grand Marquis with one of our 4 best-selling Rear Differential Cover Gaskets, earning an average 4.5 stars rating across 121 reviews.

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

    Axle Housing Cover Gasket Rectangular Shaped, 10 Bolt Hole Gasket

    from

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

    Product Features:
    • Meets or exceeds all original equipment specifications
    • Application specific design to ensure a perfect fit
    • Engineered for the sealing repair environment
    • Validated for fit, form and function
    • Unsurpassed quality you can trust
    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

    Yukon Gear – 7.5" Ford Cover Gasket (Part No.23009)

    7.5" Ford Cover Gasket

    from

    $9.99
    7.5″ Ford cover gasket.

    Product Features:
    • Cover gasket
    • Fits Ford 7.5″
    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

    Top-Quality Differential Covers for 1991 Mercury Grand Marquis

    Choose a high-quality OEM or aftermarket Differential Cover for Mercury Grand Marquis and enjoy top-notch performance from $42.99.

    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

    Yukon Gear – Chrome Cover For 8.8" Ford (Part No.32009)

    Chrome Cover For 8.8" Ford

    from

    $74.99
    Chrome cover for 8.8″ Ford.

    Product Features:
    • Fits Ford 8.8″
    • Chrome
    See More

    Yukon Gear – Chrome Cover For 7.5" Ford (Part No.32008)

    Chrome Cover For 7.5" Ford

    from

    $42.99
    Chrome cover for 7.5″ Ford.

    Product Features:
    • Fits Ford 7.5″
    • Chrome
    See More

    Yukon Gear – 8.8" Ford Low Profile Ta HD Aluminum Rear Cover (Part No.32114)

    8.8" Ford Low Profile Ta HD Aluminum Rear Cover

    from

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

    Product Features:
    • Fits Ford 8.8″
    • Aluminum girdle cover
    See More

    Top Picks for 1991 Mercury Grand Marquis Differential Bearings

    Invest in one of our 7 durable Differential Bearings for your 1991 Mercury, knowing you’re getting trusted brands and expert craftsmanship.

    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 – Bearing – TRB (Tapered Roller Bearing) (Part No.KT11)

    Bearing - TRB (Tapered Roller Bearing)

    from

    $21.79
    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.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
    See More

    National – Bearing Race (Part No.JL69310)

    Bearing Race

    from

    $7.29
    Product Features:
    • PREMIUM MATERIALS: Precision manufactured using premium-grade steel for outstanding durability and performance
    • SMOOTH ROTATION: Crowned raceways for even load distribution
    • OE-STYLE DESIGN: Engineered to meet OE specifications
    • COMPREHENSIVE COVERAGE: Industry-leading coverage for domestic and import applications
    • RIGOROUS TESTING: Comprehensive testing throughout design and development processes by National engineers for quality you can count on
    See More

    Yukon Gear – Cross Pin Bolt (Part No.33067)

    Cross Pin Bolt

    from

    $6.99
    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
    See More

    Top-Rated Differential Oil for 1991 Mercury Grand Marquis

    Make a smart move for your 1991 Mercury Grand Marquis with products all priced from $11.99 to $148.99.

    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
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    Yukon Gear – Redline Synthetic "Shock Proof" Oil – 3 Quarts (Part No.15000)

    Redline Synthetic "Shock Proof" Oil - 3 Quarts

    from

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

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

    Redline Synthetic "Shock Proof" Oil - 4 Quarts

    from

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

    Product Features:
    • Includes four quarts of Redline Shockproof oil
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    Top-Rated Differential Brands For Your 1991 Mercury Grand Marquis

    When it comes to finding the perfect Differential for your 1991 Mercury Grand Marquis, 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 FELPRO, National, and Motive Gear, and more, all known for their exceptional customer ratings (average brand rating of 4.6 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 Grand Marquis, providing peace of mind with parts that meet or exceed OEM standards.

    Popular FELPRO 1991 Mercury Grand Marquis Differentials

    If you’re looking for a top-quality Differential for your 1991 Mercury Grand Marquis, Advance Auto Parts has exactly what you need with our selection of FELPRO Differentials. We have 2 FELPRO Differentials in stock for this fitment, all known for their durability and precision fit. With prices starting at just $14.99 and an average cost of $15.49, you’ll find the perfect Differential for your needs and budget. FELPRO Differentials for the 1991 Mercury Grand Marquis come highly rated, with over 124 customer reviews and an impressive average rating of 4.6 stars. Choosing a FELPRO Differential from Advance Auto Parts is a smart move to ensure quality and value for your vehicle.
    Axle Housing Cover Gasket Rectangular Shaped, 10 Bolt Hole Gasket
    from $15.99
    (121)
    Axle Housing Cover Gasket Rectangular Shaped, 10 Bolt Hole Gasket
    “Getting the parts were cheaper than the competition and fast easy help!”
    Axle Housing Cover Gasket Oval Shaped 10 Bolt Hole Gasket
    from $14.99
    (3)
    Axle Housing Cover Gasket Oval Shaped 10 Bolt Hole Gasket
    “Perfect fit for 99 V6 mustang differential.”

    Top-Quality National 1991 Mercury Grand Marquis Differentials

    For those in search of a high-quality Differential for their 1991 Mercury Grand Marquis, 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.
    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.”
    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 1991 Mercury Grand Marquis Differentials

    What are the best-selling Differentials for 1991 Mercury Grand Marquis?

    Out of 224 Differentials that fit 1991 Mercury Grand Marquis, the following parts are the top sellers:

    What’s the price range for 1991 Mercury Grand Marquis Differentials?

    The prices of Differentials for the 1991 Mercury Grand Marquis range from $1.29 up to $2,064.99 for the most premium parts.

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

    The average price for Differentials for the 1991 Mercury Grand Marquis is $283.49. 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 Grand Marquis model years?

    Yes, we carry Differentials for 35 model years of Mercury Grand Marquis between 1975 and 2011. The following model years are the most popular for Differential purchases: 2011, 2010, 2009, 2008, 2007, 2006, 2005, 2004, and 2003.

    What are the cheapest Differentials for my 1991 Mercury Grand Marquis?

    The cheapest 1991 Mercury Grand Marquis 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 Cougar 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 Grand Marquis?

    Based on 667 reviews by customers, our 1991 Mercury Grand Marquis Differentials have an average customer rating of 4 stars. These are the highest-rated categories of Differentials for the 1991 Mercury Grand Marquis and their top-rated products:

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

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

    Can I get help with 1991 Mercury Grand Marquis 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 Grand Marquis Differentials?

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