USA Standard Master Overhaul Kit For Toyota 7.5in IFS Diff For T100 / Tacoma / and Tundra
A howl from the front of a four-wheel-drive Tacoma, T100 or Tundra that changes with throttle, a wet pinion seal under the front axle, or a growl that only shows up with the front hubs and 4WD engaged usually traces back to the 7.5-inch independent front differential. This USA Standard Gear master overhaul kit, part number ZK T7.5-REV-FULL, is the complete bearing, seal and shim package for rebuilding that front differential, or for setting up a new ring and pinion in it.
The Toyota 7.5 front unit is a reverse-rotation design: because it sits in front of the transfer case and is driven from the other direction, its gear set is cut for the opposite rotation of a rear axle, and ring and pinion sets for it are sold as reverse-rotation parts. Inside, the pinion rides on two tapered roller bearings held at a set preload by a crush sleeve, and the carrier spins on two side bearings whose position, set with shims, decides both carrier preload and ring gear backlash. When those bearings wear, the gear mesh drifts and the teeth start to sing. This kit replaces every one of those wear and setup parts at once.
Per the manufacturer, ZK T7.5-REV-FULL includes Koyo carrier bearings and races, Koyo pinion bearings and races, the pinion seal, axle seals, a complete shim kit, ring gear bolts, a new pinion nut, a crush sleeve, oil baffles and slingers, thread locker, gear marking compound with a brush, and silicone for the cover. The FULL suffix matters: the shorter ZK T7.5-REV kit lists only a pinion shim kit, while this one carries the complete shim set for the carrier side as well.
Drain the front differential and look at the oil and the magnet. Fine gray paste is normal wear; flakes or bearing cage pieces mean the bearings are done. With the front driveshaft unbolted, rock the pinion flange up and down: any vertical play means worn pinion bearings. Then drive the truck in 2WD and 4WD. If the noise only appears with the front axle engaged, the front differential is your suspect. If it is there in both modes, check the CV shafts and wheel bearings first; a worn front CV axle pair can fool you into blaming the gears.
The manufacturer lists this kit for the reverse-rotation Toyota 7.5-inch front differential, and the title names the T100, Tacoma and Tundra. Not every one of those trucks has the reverse-rotation front, so check yours before you buy. Toyota built this front unit in four-cylinder and V6 forms, and bearing sizes differ between them; that is why separate four-cylinder and V6 kits exist, such as the four-cylinder-only bearing install kit. Before ordering, compare the numbers on your old bearings and races to the kit, or send us your year, engine and VIN and we will check it. Do not use it on a Toyota rear axle; the rear T100 and Tacoma differential takes a different kit. You can browse more axle kits in our rebuild kits category.
Pull the front differential from the truck, mark the bearing caps, and record the old backlash before teardown. Press the new races in fully, set pinion depth with the supplied shims, and use the new crush sleeve and pinion nut to bring pinion bearing preload up slowly; overshooting a crush sleeve means starting over with another sleeve. Shim the carrier for preload and backlash, then paint the gear teeth with the marking compound and read the contact pattern before closing it up. Coat the ring gear bolts with the included thread locker and torque them to the factory figure. Fill with the hypoid gear oil grade your owner manual calls for. If you are changing ratio at the same time, pair the kit with a reverse-rotation set like the Yukon 4.88 reverse gear set, and break the new gears in gently for the first few hundred miles.
| Brand | Yukon Gear & Axle |
| Part number | ZK T7.5-REV-FULL |
| Fits | USA Standard Master Overhaul Kit For Toyota 7.5in IFS Diff For T100 / Tacoma / and Tundra |
| Type | Differential Overhaul Kits |
| Condition | New |
| Ships | Same business day (in stock), from the USA |
| Warranty | 1-year |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
No. ZK T7.5-REV-FULL is for the reverse-rotation 7.5-inch independent front differential. The rear differential on T100 and Tacoma trucks uses a different master kit.
The shorter ZK T7.5-REV is listed with a pinion shim kit only. The FULL version adds a complete shim kit and axle seals, so you can set carrier preload and backlash and reseal the sides without ordering extra parts.
Toyota used different bearing sizes in four-cylinder and V6 versions of this front differential. Compare the numbers on your old bearings and races to the kit before installing, or send us your year, engine and VIN and we will confirm.
Yes, if the teeth are not pitted or chipped. Record the old backlash and pinion depth shims at teardown, then set the gears back up with the new bearings and check the contact pattern with the included marking compound.
Use the hypoid gear oil grade and capacity listed in your owner manual for the front differential. Change it again after the first few hundred miles if you installed new gears.
