Yukon Gear Master Overhaul Kit For 79-97 GM 9.5in Semi-Float Diff

From 1979 through 1997, GM put a 9.5 in. ring gear semi-float axle with a 14-bolt cover under many of its light-duty three-quarter-ton pickups, Suburbans and vans. It looks a lot like the famous full-float 14-bolt from the back, but inside it is a different axle with its own bearings. If yours has started to howl at cruising speed, drone when you pull a trailer, or leak at the pinion, the Yukon Gear & Axle YK GM9.5-A master overhaul kit gives you the full set of bearings, races and seals to rebuild it for the 1997-and-earlier version of this axle.

What this kit does in the GM 9.5 in. semi-float

On the semi-float 14-bolt, the axle shafts carry the weight of the truck and are held in the carrier by C-clips, while the pinion rides on two tapered bearings preloaded by a crush sleeve and nut. The carrier side bearings and their shims set backlash between the 9.5 in. ring gear and the pinion. Worn rollers let those settings drift, the tooth contact walks off center and the noise grows until the gears themselves are damaged. This kit replaces the wear parts with Timken carrier and pinion bearings and races, and adds the pinion seal, a complete shim kit, ring gear bolts, a new pinion nut and crush sleeve, thread locker, gear marking compound with a brush, and a cover gasket.

Symptoms of a worn 9.5 semi-float

• Whine on acceleration, on coast, or both, that rises with road speed
• A steady growl that gets louder with a load in the bed or a trailer behind
• Driveline clunk when shifting into drive or reverse, or noticeable in-and-out play at the yoke
• Gear oil on the pinion seal, the yoke or the cover edge
• Fine metal on the fill plug or drain area when the oil is changed

How to confirm it before you buy

First make sure it is the 9.5 semi-float and not the 10.5 full-float. On a semi-float, the axle shaft ends at the wheel mounting surface and there is no hub with a ring of bolts poking out of the wheel. Six-lug trucks are semi-float, but some 8-lug trucks and G30 vans used the semi-float too, so do not go by lug count alone. Then drain the oil and pull the cover: if the gear teeth are clean and the noise is bearing-type rumble or whine, this kit is the repair. If the full-float 10.5 is what you have, see the GM 14-bolt 10.5 master overhaul kit instead.

Fitment

Yukon lists this kit for the 1997-and-earlier GM 9.5 in. semi-float differential, the axle GM ran from 1979 through 1997. GM kept building a 9.5 in. semi-float after 1997 with different parts, so a 1998-or-later truck needs a different kit. Match the cover shape, ring gear size and build year, or send us your year and VIN and we will confirm it. Shop more axle kits in our rebuild kits collection, where you will also find the USA Standard version of the 79-97 GM 9.5 kit.

Install notes

• Remove the cross-pin retaining bolt and cross pin, push the axle shafts in and take out the C-clips before the shafts and carrier can come out
• Mark the side bearing caps so each goes back on its own side in the same direction
• Drive in new races squarely with a bearing race and seal driver set
• Tighten the pinion nut in small steps and check rotating torque often; overshooting the crush sleeve means starting over with another sleeve
• Read the pattern with the included compound, and if worn spider gears showed up during teardown, add the 33-spline GM 9.5 spider gear set
• Axle shaft bearings and seals are not part of this kit, so check them while the shafts are out
• Refill with the GL-5 gear oil your owner's manual calls for

Will this fit my 1999 Silverado 2500 with a 9.5 rear?

No. This kit is for the 1997-and-earlier GM 9.5 in. semi-float. Later 9.5 axles use different parts, so order the kit for your axle's years.

My truck has 8 lugs. Can it still be a 9.5 semi-float?

Yes. Some 8-lug trucks and G30 vans used the 9.5 semi-float. If there is no hub protruding past the wheel with its own bolts, you most likely have the semi-float.

What comes in the YK GM9.5-A kit?

Timken carrier and pinion bearings and races, pinion seal, complete shim kit, ring gear bolts, pinion nut, crush sleeve, thread locker, marking compound with brush, and a cover gasket.

Does it include axle bearings and seals?

No. Axle shaft bearings and seals are separate, so inspect them while the shafts are out for the C-clips.

Can I keep my factory gears?

Yes, if the teeth have no chips or pitting. Use the original pinion shim as a baseline and verify the pattern with the included marking compound.