How do you properly replace the pinion seal and reassemble the rear differential on Ford Mustang?

Raise the rear of the vehicle and place it securely on jackstands, then remove the rear wheels, brake calipers, and brake discs. Mark the driveshaft and companion flange for ease of realignment during reassembly, then remove the driveshaft. Mark the relationship between the pinion and companion flange. Using an inch-pound torque wrench, measure and record the torque required to turn the pinion nut through several revolutions, which will be used when the pinion flange is reinstalled. Hold the companion flange with a suitable tool and remove the pinion nut, then use a small puller if necessary to separate the pinion flange from the pinion shaft. Pry out the old seal with a seal removal tool, clean the oil seal mounting surface, and tap the new seal into place, ensuring it is inserted squarely. Inspect the splines on the pinion shaft for burrs and nicks, removing any rough areas with a crocus cloth and wiping the splines clean. Install the companion flange, aligning it with the marks made during removal, and gently tap it on with a soft-faced hammer until the pinion nut can be started on the pinion shaft. Hold the companion flange while tightening the pinion nut, stopping frequently to take rotational torque measurements until the previously recorded measurement is reached. If the recorded measurement was less than the pinion bearing preload torque, continue tightening until the specified torque is reached; if it was more, continue until the recorded measurement is reached, avoiding backing off the nut to reduce preload. Reinstall the driveshaft, brake discs, brake calipers, and wheels, check the differential oil level and fill as necessary, then lower the vehicle and take a test drive to check for leaks.

Genuine Ford Mustang Differential Seal

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4 Differential Seals found

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Ford Mustang Seal Assembly - Oil
Part Number: BR3Z-4676-A
$13.22 MSRP: $18.83
You Save: $5.61 (30%)
Ships in 1-2 Business Days
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Product Specifications
- Other Name: Seal Assy - Oil; Oil Seal, Pinion Gear Seal, Pinion Seal
- Replaces: E8TZ-4676-C, F89Z-4676-AA
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 1980-2014 Ford Mustang | 4 Cyl 2.3L, 6 Cyl 3.3L, 6 Cyl 3.7L PFI NA, 6 Cyl 3.8L, 6 Cyl 3.8L OHV EFI, 6 Cyl 3.9L OHV EFI NA, 6 Cyl 4.0L SOHC EFI, 8 Cyl 4.2L, 8 Cyl 4.6L, 8 Cyl 4.6L DOHC EFI, 8 Cyl 4.6L DOHC EFI S/C, 8 Cyl 4.6L SOHC EFI, 8 Cyl 5.0L, 8 Cyl 5.0L DOHC EFI Modular, 8 Cyl 5.0L MOD DOHC SEFI NA, 8 Cyl 5.4L, 8 Cyl 5.4L DOHC EFI S/C ALUM, 8 Cyl 5.8L, 8 Cyl 5.8L DOHC SC | 3AT C3, 3AT C4, 3AT C5, 4-Speed Automatic Transmission 4R70W (AODE), 4AT 4R70W, 4AT 4R75W, 4AT A4LD, 4AT AOD, 4AT AOD-E, 4MT, 5-Speed Automatic Transmission 5R55S, 5-Speed Manual Transmission (T450D), 5-Speed Manual Transmission T5OD, 5-Speed Manual Transmission TR3650, 5MT, 6-Speed Automatic Transmission (6R80), 6-Speed Manual Transmission (T56), 6-Speed Manual Transmission Tremec T56, 6-Speed Manual Transmission-MT82, Left Hand Drive, Rear-Wheel Drive (Left Hand Drive)
View related parts
Ford Mustang Seal Assembly - Oil
Part Number: F89Z-4676-AA
$13.22 MSRP: $18.83
You Save: $5.61 (30%)
Ships in 1-2 Business Days
ADD TO CART
Product Specifications
- Other Name: Seal Assy - Oil
- Replaced by: BR3Z-4676-A
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 1999-2011 Ford Mustang | 6 Cyl 3.7L PFI NA, 6 Cyl 3.8L, 6 Cyl 3.8L OHV EFI, 6 Cyl 3.9L OHV EFI NA, 6 Cyl 4.0L SOHC EFI, 8 Cyl 4.6L, 8 Cyl 4.6L DOHC EFI, 8 Cyl 4.6L DOHC EFI S/C, 8 Cyl 4.6L SOHC EFI, 8 Cyl 5.0L MOD DOHC SEFI NA, 8 Cyl 5.4L, 8 Cyl 5.4L DOHC EFI S/C ALUM, 8 Cyl 5.8L DOHC SC | 4-Speed Automatic Transmission 4R70W (AODE), 4AT 4R70W, 4AT 4R75W, 5-Speed Automatic Transmission 5R55S, 5-Speed Manual Transmission (T450D), 5-Speed Manual Transmission T5OD, 5-Speed Manual Transmission TR3650, 5MT, 6-Speed Automatic Transmission (6R80), 6-Speed Manual Transmission (T56), 6-Speed Manual Transmission Tremec T56, 6-Speed Manual Transmission-MT82, Left Hand Drive, Rear-Wheel Drive (Left Hand Drive)
- 1980-1989 Ford Mustang | 4 Cyl 2.3L, 6 Cyl 3.3L, 6 Cyl 3.8L, 8 Cyl 4.2L, 8 Cyl 5.0L | 3AT C3, 3AT C4, 3AT C5, 4AT A4LD, 4AT AOD, 4MT, 5MT
View related parts
Ford Mustang Seal Assembly - Oil
Part Number: BL3Z-4676-A
$15.56 MSRP: $22.17
You Save: $6.61 (30%)
Ships in 1 Business Day
ADD TO CART
Product Specifications
- Other Name: Seal Assy - Oil; Front Seal, Oil Seal, Pinion Seal, Rear Seal, Seal
- Replaces: 1L3Z-4676-A, E8TZ-4676-B, NL3Z-4676-A
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 2015-2023 Ford Mustang | 4 Cyl 2.3 L GAS, 4 Cyl 2.3L TIVCT DI TC, 6 Cyl 3.7L PFI NA, 8 Cyl 5.0 L GAS, 8 Cyl 5.0L DOHC EFI Modular, 8 Cyl 5.0L MOD DOHC SEFI NA, 8 Cyl 5.2 L GAS, 8 Cyl 5.2L | 10-Speed Automatic Transmission (10R80), 6-Speed Automatic Transmission (6R80), 6-Speed Manual Transmission-3160, 6-Speed Manual Transmission-MT82, Left Hand Drive, Rear-Wheel Drive (Left Hand Drive)
View related parts
Ford Mustang Seal Assembly - Oil
Part Number: E8TZ-4676-C
$13.22 MSRP: $18.83
You Save: $5.61 (30%)
Ships in 1-2 Business Days
ADD TO CART
Product Specifications
- Other Name: SEAL ASY - OIL
- Replaced by: BR3Z-4676-A
- Warranty: This genuine part is guaranteed by Ford's factory warranty.
Fits the following Vehicles:
- 1990-1998 Ford Mustang | 4 Cyl 2.3L, 6 Cyl 3.8L, 8 Cyl 4.6L, 8 Cyl 5.0L, 8 Cyl 5.8L | 4AT 4R70W, 4AT A4LD, 4AT AOD, 4AT AOD-E, 5MT

Ford Mustang Differential Seal

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Ford Mustang Differential Seal Parts Questions & Experts Answers

Seal Assembly - Oil
F89Z-4676-AA
Q: How do you properly replace the pinion seal and reassemble the rear differential on Ford Mustang?
A: Raise the rear of the vehicle and place it securely on jackstands, then remove the rear wheels, brake calipers, and brake discs. Mark the driveshaft and companion flange for ease of realignment during reassembly, then remove the driveshaft. Mark the relationship between the pinion and companion flange. Using an inch-pound torque wrench, measure and record the torque required to turn the pinion nut through several revolutions, which will be used when the pinion flange is reinstalled. Hold the companion flange with a suitable tool and remove the pinion nut, then use a small puller if necessary to separate the pinion flange from the pinion shaft. Pry out the old seal with a seal removal tool, clean the oil seal mounting surface, and tap the new seal into place, ensuring it is inserted squarely. Inspect the splines on the pinion shaft for burrs and nicks, removing any rough areas with a crocus cloth and wiping the splines clean. Install the companion flange, aligning it with the marks made during removal, and gently tap it on with a soft-faced hammer until the pinion nut can be started on the pinion shaft. Hold the companion flange while tightening the pinion nut, stopping frequently to take rotational torque measurements until the previously recorded measurement is reached. If the recorded measurement was less than the pinion bearing preload torque, continue tightening until the specified torque is reached; if it was more, continue until the recorded measurement is reached, avoiding backing off the nut to reduce preload. Reinstall the driveshaft, brake discs, brake calipers, and wheels, check the differential oil level and fill as necessary, then lower the vehicle and take a test drive to check for leaks.