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Yukon Gear YK T8-A Master Overhaul Kit for Toyota 8in Differential (1985 and Older)
The YK T8-A is a complete rebuild kit built for the Toyota 8in differential in applications from 1985 and older, or any year using an aftermarket ring and pinion. Designed for the Toyota 4Runner and Pickup truck, the YK T8-A bundles everything you need for a full professional-grade overhaul: Timken bearings, precision shims, seals, and all fasteners. When your vintage Toyota diff is showing wear, the YK T8-A complete rebuild kit from Yukon Gear gets you back on the road or trail with confidence.
Features and Benefits
- Genuine Timken carrier bearings and pinion bearings for reliable, long-lasting performance
- Precision ground shim sets for pinion depth and carrier preload adjustment
- High-quality pinion seal and axle seals designed for Toyota 8in dimensions
- Compatible with aftermarket ring and pinion gear sets of any production year
- Ring gear bolts, pinion nut, and crush sleeve included for a complete hardware refresh
- Gear marking compound and brush for verifying ring-and-pinion contact pattern during setup
- Thread-locking compound for ring gear bolt installation
- Differential cover gasket included for a clean, leak-free finish
- All components sourced and quality-controlled by Yukon Gear
Fitment
| Year | Make | Model | Notes |
|---|---|---|---|
| 1984 | Toyota | 4Runner | Toyota 8in, 1985 and older or aftermarket R&P |
| 1985 | Toyota | 4Runner | Toyota 8in, 1985 and older or aftermarket R&P |
| 1979 | Toyota | Pickup | Toyota 8in, 1985 and older or aftermarket R&P |
| 1980 | Toyota | Pickup | Toyota 8in, 1985 and older or aftermarket R&P |
| 1981 | Toyota | Pickup | Toyota 8in, 1985 and older or aftermarket R&P |
| 1982 | Toyota | Pickup | Toyota 8in, 1985 and older or aftermarket R&P |
| 1983 | Toyota | Pickup | Toyota 8in, 1985 and older or aftermarket R&P |
| 1984 | Toyota | Pickup | Toyota 8in, 1985 and older or aftermarket R&P |
| 1985 | Toyota | Pickup | Toyota 8in, 1985 and older or aftermarket R&P |
Specifications
| Specification | Detail |
|---|---|
| Part Number | YK T8-A |
| UPC | 883584141174 |
| Differential | Toyota 8in |
| Ring Gear Size | 8 inches |
| Application | 1985 and older, or any year with aftermarket ring and pinion |
| Bearings Included | Timken carrier bearings and pinion bearings with races |
| Seals Included | Pinion seal, axle seals |
| Shim Set | Complete pinion depth and carrier shim set |
| Warranty | Yukon Gear limited warranty |
What's Included
- Timken carrier bearings with races (2 sets)
- Timken pinion bearings with races (front and rear)
- Pinion seal
- Axle seals (pair)
- Complete pinion depth shim set
- Complete carrier shim set
- Ring gear bolts
- Pinion nut
- Crush sleeve
- Thread-locking compound
- Gear marking compound with brush
- Differential cover gasket
Frequently Asked Questions
Q: What is the difference between the YK T8-A and YK T8-B?
A: The YK T8-A is for Toyota 8in differentials from 1985 and older, or any year running an aftermarket ring and pinion. The YK T8-B is calibrated for 1986 and newer Toyota 8in differentials using OEM ring and pinion gears.
Q: Can I use this kit with a newer aftermarket ring and pinion in a 1990 4Runner?
A: Yes. The YK T8-A complete rebuild kit is also appropriate when installing an aftermarket ring and pinion in any model year Toyota 8in differential.
Q: Are the bearings in this kit genuine Timken?
A: Yes. The YK T8-A includes genuine Timken carrier and pinion bearings with races for both positions.
Q: Will installing aftermarket parts void my vehicle warranty?
A: Under the Magnuson-Moss Warranty Act, a vehicle manufacturer cannot void your powertrain warranty solely because you installed aftermarket parts. Warranty denial requires proof the aftermarket part caused the specific failure.
Q: Does this kit include a crush sleeve?
A: Yes, the YK T8-A includes a crush sleeve along with a pinion nut and ring gear bolts for a complete hardware refresh.
Q: What vehicles does this kit fit?
A: The YK T8-A fits the Toyota 4Runner from 1984 to 1985 and the Toyota Pickup from 1979 to 1985 with the Toyota 8in differential.
Q: Do I need additional parts beyond this kit?
A: You will need gear oil matching Toyota specifications. If you are changing the gear ratio, you will need a ring and pinion set separately. All rebuild hardware is included in the YK T8-A.
Q: Is professional installation recommended?
A: Differential rebuilds require precise preload and backlash settings. Professional or experienced DIY installation with appropriate tooling is strongly recommended for best results.
Installation Instructions
- Drain the differential gear oil and remove rear axle shafts per your Toyota service manual.
- Remove the differential cover and clean all mating surfaces thoroughly.
- Remove the carrier assembly and inspect the housing for wear or scoring.
- Remove the pinion shaft and record original shim stack thickness.
- Press off old pinion bearings and install the new Timken pinion bearings from the YK T8-A kit.
- Use the included shim set to establish the correct pinion depth; confirm with a dial indicator.
- Press new carrier bearings and races onto the carrier assembly.
- Install the carrier, set ring-and-pinion backlash to Toyota specification, and verify contact pattern with marking compound.
- Apply thread-locking compound to ring gear bolts and torque to specification.
- Install the new pinion seal and torque the pinion nut to achieve proper bearing preload.
- Install new axle seals, reinstall axle shafts, and torque all fasteners to spec.
- Install the differential cover with the new gasket and fill with the appropriate Toyota-spec gear oil.
- Road test and check for leaks after the initial break-in period.
California Proposition 65 Warning: This product can expose you to chemicals including lead and lead compounds, which are known to the State of California to cause cancer, birth defects, and other reproductive harm. For more information, visit www.p65warnings.ca.gov.
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