1991 Ford Thunderbird Differentials

Keep Your 1991 Ford Thunderbird in Top Shape with Quality Differentials

Whether you’re repairing or upgrading your Differential, using high-quality parts is key to keeping your 1991 Ford Thunderbird looking sharp and performing at its best. At Advance Auto Parts we carry a wide selection of dependable options, including Differential Bearings, Rear Differential Cover Gaskets, and Differential Oil. Whether you’re replacing a damaged part or enhancing your truck’s style and protection, you’ll find exactly what you need to get the job done right.

Top-Rated Differentials from Trusted Brands

Looking for a reliable Differential? We’ve got you covered with options from brands you know and trust like Motive Gear, National, and Valvoline. For example, Motive Gear Differentials start at just $7.99 with an average 4.0 star rating. National and Valvoline offer similar pricing and quality, backed by strong customer feedback. With over 1,731 reviews and a solid 4 star average, you can shop with confidence knowing other Ford Thunderbird owners approve.

Competitive Prices and Extensive Inventory

The average price for a 1991 Ford Thunderbird Differential at Advance Auto Parts is around $193.39, with a range that starts at $1.29 and goes up to $1,115.99. With 166 options in stock from 19 trusted brands, finding the right fit is easy. Popular picks like High Performance 5W-30 Synthetic Engine Oil, Better Wear Protection, 5 Quart, DEX/MERC ATF Conventional Automatic Transmission Fluid, 1 Quart, and Differential Shaft Lock Bolt start at just $6.79 and offer a great balance of form and function.

Explore Related Parts

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

Essential 1991 Ford Thunderbird Differentials

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.
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Yukon Gear – The Carrier Bearing Puller (Part No.56072)

The Carrier Bearing Puller

from

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

Product Features:
  • Carrier bearing puller
  • Works with an impact gun to safely and easliy remove carrrier bearings
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Yukon Gear – Pinion Install Kit For Ford 7.5" Differential (Part No.13039)

Pinion Install Kit For Ford 7.5" Differential

from

$184.99
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, 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 7.5″
  • 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 – Shim Kit For 9" Ford Tracloc Clutch (Part No.16030)

Shim Kit For 9" Ford Tracloc Clutch

from

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

Product Features:
  • Shim kit
  • Fits Ford 8″ and 9″ Trac Loc
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Yukon Gear – Cover Bolt For Ford 7.5", 8.8" & 9.75" (Part No.33554)

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

from

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

Product Features:
  • 35 spline
  • 8 x 3.96″ bolt pattern
  • Cut to length design fits 40″-43.5″ applications
  • Fits Dana Spicer 60, 70 and 80
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Yukon Gear – Flat Side Gear Without Hub For 9" Ford With 31 Splines (Part No.16162)

Flat Side Gear Without Hub For 9" Ford With 31 Splines

from

$46.99
Flat side gear without hub for 9″ Ford with 31 splines.

Product Features:
  • Side gear without hub
  • Fits Ford 8″ and 9″ Trac Loc positraction with 31 spline axles
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Felpro – Axle Housing Cover Gasket Oval Shaped 10 Bolt Hole Gasket (Part No.RDS 55393)

Axle Housing Cover Gasket Oval Shaped 10 Bolt Hole Gasket

from

$7.49
Fel-Pro® gaskets are specifically designed for the repair environment to deliver a reliable seal on even the most troublesome applications. Designed for imperfect sealing surfaces and manufactured with proprietary materials, you can count on Fel-Pro for innovative sealing solutions for the real-world repair environment.

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

National – Bearing Race (Part No.M88010)

Bearing Race

from

$7.99
Manufactured with premium-grade steel, National taper bearing cups feature crowned raceways to ensure even load distribution.

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

Yukon Gear – Forged Yoke For Ford 9" With 35 Spline Pinion And A 1350 U/Joint Size (Part No.41065)

Forged Yoke For Ford 9" With 35 Spline Pinion And A 1350 U/Joint Size

from

$209.99
Yukon forged yoke for Ford 9″ with 35 spline pinion and a 1350 U/joint size (stronger than billet). 3.625″ snap ring span, 1.188″ cap diameter. Outside snap ring. All Yukon yokes come with a one year warranty against manufacturing defects.

Product Features:
  • Fits Ford 9″
  • 35 spline
  • 1350 u-joint size
  • 3.625″ snap ring span
  • 1.188″ cap diameter
  • Outside snap ring design
  • U-bolt style
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Yukon Gear – Cross Pin Bolt (Part No.33067)

Cross Pin Bolt

from

$6.99
Cross pin bolt for Chrysler 8.25″, 9.25″ rear, Ford 7.5″, 8.8″, GM 12 bolt car & truck, 7.2″ IFs, 7.5″, 7.6″, 8.0″, 8.25″ IFS & 8.5″.

Product Features:
  • Cross pin bolt for Chrysler 8.25″ and 9.25″ rear, Ford 7.5″ and 8.8″, GM 12 botl car and truck, 8.5″, 8.25″ IFS, 8.0″, 7.625″, 7.5″ and 7.2″ IFS
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Motive Gear – Differential Pinion Nut (Part No.379570S)

Differential Pinion Nut

from

$6.99
All Motive Gear products are engineered for their specific application and manufactured in state of the art facilities. All of our products undergo rigid quality control processes to insure proper fit, performance and longevity. Motive Gear products can be found in the winners circle at NHRA, IHRA, NMRA, NMCA, SODA, SCORE, BITD, Ultra-4 and NASCAR events because we offer unmatched selection and quality demanded by racers and their crew chiefs – the same quality and selection demanded by DIY customers and top mechanics. With four warehouses strategically located across North America, most Motive Gear orders arrive within 2-4 days. Win with Motive Gear!
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USA Standard Gear – Ring & Pinion Gear Set For Ford 8.8" In A 3.08 Ratio (Part No.36120)

Ring & Pinion Gear Set For Ford 8.8" In A 3.08 Ratio

from

$359.99
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 standard rotation Ford 8.8″
  • 8.80″ ring gear diameter
  • 30 spline pinion
  • 10 ring gear bolts
  • 3.08 ratio
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Yukon Gear – Pinion Seal For ’61-’85 9" Ford (Part No.30137)

Pinion Seal For '61-'85 9" Ford

from

$17.99
Pinion seal for ’61-’85 9″ Ford. 3″ OD.Yukon Mighty seal.

Product Features:
  • Pinion seal
  • Fits 1961-1985 Ford 9″
  • 3.00″ O.D.
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Yukon Gear – Dura Grip Positraction For Ford 8.8" With 28 Spline Axles (Part No.26005)

Dura Grip Positraction For Ford 8.8" With 28 Spline Axles

from

$834.99
The Yukon Dura Grip provides aggressive yet smooth traction to give you the confidence & performance you need. Get longer life and better traction with the heavy duty Yukon Dura Grip Positraction. The Yukon Dura Grip uses a nodular case and forged 4320 internals for added strength along with composite clutches for high performance and long life. All units are Rebuildable and many offer upgrades to increase aggressiveness for racing applications. Each unit carries a one year warranty against defects.

Product Features:
  • Fits Ford 8.8″ with 28 spline axles
  • 4-spring, clutch style positraction
  • Internal gears are manufactured using forged 4320 steel and cut to provide stronger teeth
  • Fully rebuildable
  • Assembled in the USA
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National – Shaft Repair Sleeve (Part No.99114)

Shaft Repair Sleeve

from

$27.99
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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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 – Minor Install Kit For Ford 7.5" Differential (Part No.12033)

Minor Install Kit For Ford 7.5" Differential

from

$55.99
Yukon Minimum installation kits are a low cost solution for gear changes in newer vehicles where the bearings can be reused. This kit uses all high quality components to ensure a smooth set up. kit includes a pinion seal, crush sleeve (if applicable), complete shim kit, marking compound and brush.

Product Features:
  • Fits Ford 7.5″
  • Included are a pinion seal, crush sleeve, complete shim kit, marking compound and brush.
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Yukon Gear – Standard Open Carrier Case, Ford 7.5" (Part No.20071)

Standard Open Carrier Case, Ford 7.5"

from

$369.99
Product Features:
  • Standard open carrier case
  • Fits Ford 7.5″
  • Does not include spider gears
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National – Shaft Repair Sleeve (Part No.99155)

Shaft Repair Sleeve

from

$38.99
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
  • Installation tool reduces sleeve distortion and allows for installation without removal from the shaft
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Yukon Gear – 8.5" & 8.2" GM Carrier Installation Kit (Part No.57008)

8.5" & 8.2" GM Carrier Installation Kit

from

$109.99
Yukon Carrier installation kits are great, low cost kit for carrier changes such as Positraction or locker upgrades. Carrier installation kit for GM 8.2″ & 8.5″ differential. This kit contains carrier bearings, races and shims.

Product Features:
  • Fits GM 7.5″, 7.625″ 8.2″ and 8.5″
  • Includes carrier bearings and races and “super” carrier shim kit
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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 – 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
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Dorman – Differential Clutch Kit (Part No.697-780)

Differential Clutch Kit

from

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

Product Features:
  • Direct replacement – this differential clutch kit provides the necessary components for repairing the original equipment on specific vehicles
  • Quality materials – all components are built for reliable longevity and performance
  • Smart solution – provides original equipment fit and function for a competitive price compared to original manufacturer
  • Trustworthy quality – backed by team of designers and engineers in the United States
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Powertrax – Lock Right Locker (Part No.2415-LR)

Lock Right Locker

from

$442.99
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

    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
    See More

    Pro-King – Differential Crush Sleeve (Part No.761A034)

    Differential Crush Sleeve

    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

    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

    Richmond Gear – RngPnnInstlKt (Part No.83-1011-B)

    RngPnnInstlKt

    from

    $48.99
    RngPnnInstlKt

    Most Popular Differential Bearings for 1991 Ford Thunderbirds

    Enhance your 1991 Ford Thunderbird with one of the 5 Differential Bearings we have in stock, starting at just $6.99.

    National – Bearing Race (Part No.LM501314)

    Bearing Race

    from

    $9.29
    Manufactured with premium-grade steel, National taper bearing cups feature crowned raceways to ensure even load distribution.

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

    National – Multi-Purpose Bearing (Part No.A-36)

    Multi-Purpose Bearing

    from

    $27.99
    Product Features:
    • CONSISTENT PERFORMANCE: Matched cup and cone components ensure consistent performance
    • PREMIUM MATERIALS: Precision manufactured using premium-grade steel for outstanding durability and performance
    • SMOOTH ROTATION: Crowned raceways and rollers for even load distribution
    • OE-STYLE DESIGN: Engineered to meet OE specifications
    • COMPREHENSIVE COVERAGE: Industry-leading coverage for domestic and import applications
    • RIGOROUS TESTING: Comprehensive testing throughout design and development processes by National engineers for quality you can count on
    See More

    National – Tapered Roller Bearing Cone (Part No.LM501349)

    Tapered Roller Bearing Cone

    from

    $19.99
    Manufactured with premium-grade steel, National taper bearing cones feature crowned raceways and rollers to ensure even load distribution.

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

    FAG US – Cup (Part No.M88010)

    Cup

    from

    $11.29
    With advanced load-carrying capacity and compact design, tapered roller bearings are used in wheel bearings, transmissions, differentials, transfer cases and other miscellanous applications. FAG manufacturers over 100 million tapered roller bearings annually.

    Product Features:
    • High-precision and High-quality components used in all KITs
    • Coverage of classic and new high-tech solutions for the best system coverage
    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

    Best-Selling 1991 Ford Thunderbird Rear Differential Cover Gaskets

    Upgrade your Thunderbird with one of our 4 best-selling Rear Differential Cover Gaskets, earning an average 4.5 stars rating across 3 reviews.

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

    Axle Housing Cover Gasket Round Shaped 10 Bolt Hole Gasket

    from

    $8.99
    Fel-Pro® gaskets are specifically designed for the repair environment to deliver a reliable seal on even the most troublesome applications. Designed for imperfect sealing surfaces and manufactured with proprietary materials, you can count on Fel-Pro for innovative sealing solutions for the real-world repair environment.

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

    Mr. Gasket – Differential Gasket (Part No.142)

    Differential Gasket

    from

    $23.99
    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.

    Product Features:
    • .047″ thick cellulose/nitrile composite gasket material
    • Precision die cut
    • Reusable
    See More

    Yukon Gear – 8.8" Ford Cover Gasket (Part No.23011)

    8.8" Ford Cover Gasket

    from

    $12.99
    8.8″ Ford cover gasket.

    Product Features:
    • Cover gasket
    • Fits Ford 8.8″
    See More

    Pro-King – Differential Cover Gasket (Part No.762B303)

    Differential Cover Gasket

    from

    $4.99
    Pro-King is the leading supplier of transmission and driveline products in the aftermarket.

    Product Features:
    • All products are designed to meet or exceed OE quality, form, fit and funtion.
    See More

    Top-Quality Differential Oil for 1991 Ford Thunderbirds

    Choose a high-quality OEM or aftermarket Differential Oil for Ford Thunderbirds and enjoy top-notch performance from $11.99.

    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
    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

    Our Top Pick for a 1991 Ford Thunderbird Rear Housing Cover Gasket

    Invest in a durable Rear Housing Cover Gasket for your 1991 Ford, knowing you’re getting trusted brands and expert craftsmanship.

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

    Axle Housing Cover Gasket Round Shaped 10 Bolt Hole Gasket

    from

    $9.99
    Fel-Pro® gaskets are specifically designed for the repair environment to deliver a reliable seal on even the most troublesome applications. Designed for imperfect sealing surfaces and manufactured with proprietary materials, you can count on Fel-Pro for innovative sealing solutions for the real-world repair environment.

    Product Features:
    • Meets or exceeds all original equipment specifications
    • Application specific design to ensure a perfect fit
    • Unsurpassed quality you can trust
    • Validated for fit, form and function
    • Each Fel-Pro gasket, no matter how small, is engineered to exacting standards with proprietary design, engineering and manufacturing processes
    See More

    Differential Covers for 1991 Ford Thunderbirds

    Make a smart move for your 1991 Ford Thunderbird with products all priced from $52.99 to $269.99.

    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

    Spectre – Differential Cover (Part No.6073)

    Differential Cover

    from

    $52.99
    Spectre’s Differential Covers are made to OEM specifications and are triple chrome plated for a lasting shine. Designed to protect the intricate moving parts of the differential, Spectre’s covers add an extra layer of protection to the vehicle’s underside. Featuring a 10-bolt design and fits the following vehicles with 7.5 inch ring gears: 1979-2003 Ford Mustang/Capri V8, 1982-2003 Ford Ranger, 1984-1997 Ford Aerostar, 1982-1992 Ford Bronco II, and 1994-2003 Mazda 2300/3000 differentials. Includes 10 SAE standard chrome bolts for installation. You’ll need to supply your own bolts if your application requires metric bolts.

    Product Features:
    • 10 chrome 5/16 inch -18 x 3/4 inch differential cover bolts
    • 10-bolt design
    • Triple chrome plated for a lasting shine
    • Precision engineered for a perfect fit
    See More

    B & M – Rear End Cover 1 EA B&M (Part No.40297)

    Rear End Cover 1 EA B&M

    from

    $269.99
    B&M Cast Aluminum Differential Covers are designed to strengthen the differential by preventing case distortion and ring gear & bearing cap deflection. Constructed of A356.0-T6 aluminum, these rugged covers significantly increase the fluid capacity and dissipate heat much faster than the stock factory unit to prolong the life of your ring and pinion gears. Additional features include an engraved B&M logo, drain and fill port locations, a magnetic drain plug for catching ferrous metal particles, and complete hardware and installation instructions.

    Product Features:
    • Additional Oil Capacity
    • More Cooling Ability
    • No Dipstick Modification
    • Some Include Fluid Pickup Extension
    • Built-In Drain Plugs
    • Cast Aluminum
    See More

    Top-Rated Differential Brands For Your 1991 Ford Thunderbird

    When it comes to finding the perfect Differential for your 1991 Ford Thunderbird, Advance Auto Parts has you covered with a wide selection of high-quality OEM and aftermarket options from 19 trusted brands. We carry the most popular Differential brands including Valvoline, National, and Motive Gear, and more, all known for their exceptional customer ratings (average brand rating of 4.8 stars) and competitive prices, as low as $7.99. Purchasing a Differential from us here at Advance Auto Parts is a smart move for both you and your 1991 Ford Thunderbird, providing peace of mind with parts that meet or exceed OEM standards.

    Popular Valvoline 1991 Ford Thunderbird Differentials

    If you’re looking for a top-quality Differential for your 1991 Ford Thunderbird, Advance Auto Parts has exactly what you need with our selection of Valvoline Differentials. We have 1 Valvoline Differentials in stock for this fitment, all known for their durability and precision fit. With prices starting at just $69.99, you’ll find the perfect Differential for your needs and budget. Valvoline Differentials for the 1991 Ford Thunderbird come highly rated, with over 364 customer reviews and an impressive average rating of 4.8 stars. Choosing a Valvoline Differential from Advance Auto Parts is a smart move to ensure quality and value for your vehicle.

    Top-Quality National 1991 Ford Thunderbird Differentials

    For those in search of a high-quality Differential for their 1991 Ford Thunderbird, 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 Ford Thunderbird Differentials

    What are the best-selling Differentials for 1991 Ford Thunderbirds?

    Out of 166 Differentials that fit 1991 Ford Thunderbirds, the following parts are the top sellers:

    What’s the price range for 1991 Ford Thunderbird Differentials?

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

    What is the average price of a Differential for a 1991 Ford Thunderbird?

    The average price for Differentials for the 1991 Ford Thunderbird is $193.39. 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 Ford Thunderbird model years?

    Yes, we carry Differentials for 45 model years of Ford Thunderbirds between 1955 and 2005. The following model years are the most popular for Differential purchases: 2005, 2004, 2003, 2002, 1997, 1996, 1995, 1994, and 1993.

    What are the cheapest Differentials for my 1991 Ford Thunderbird?

    The cheapest 1991 Ford Thunderbird Differentials we carry are:

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

    Yes. We stock Differentials for 27 other popular 1991 Ford models. Some of the most popular are 1991 Mustang Differentials, 1991 E-250 Econoline Differentials, 1991 E-350 Econoline Differentials, 1991 E-150 Econoline Differentials, and 1991 F-350 Differentials.

    What are the top-rated Differentials that fit the 1991 Ford Thunderbird?

    Based on 1,731 reviews by customers, our 1991 Ford Thunderbird Differentials have an average customer rating of 4 stars. These are the highest-rated categories of Differentials for the 1991 Ford Thunderbird and their top-rated products:

    What types of Differentials do you sell for my 1991 Ford Thunderbird?

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

    Can I get help with 1991 Ford Thunderbird Differential orders?

    Contact our customer support team by chat or phone, through the help desk page, where you can find instant answers about Ford Differentials and more.

    What is your return policy for Ford Thunderbird Differentials?

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