Yukon Gear Master Overhaul Kit For 63-79 GM Ci Corvette Diff

Restoring a C2 Sting Ray or a C3 Corvette and the independent rear end whines at cruise, clunks when you lift off, or leaves oil under the car? The 1963-1979 Corvette uses a frame-mounted cast iron differential that is now decades old, and worn bearings and a hard pinion seal are typical. The Yukon Gear and Axle YK GMVET-CI master overhaul kit supplies the bearings, races, seal, shims and hardware to rebuild that center section or install a new ring and pinion.

What the master overhaul kit does in a 1963-1979 Corvette differential

On the C2 and C3 Corvette, the differential housing bolts to the frame and the half shafts run out to the rear wheels through side yokes. Inside, the pinion runs on two tapered roller bearings with preload held by a crush sleeve and nut, and a shim sets pinion depth. The carrier spins on two side bearings, and their shims set preload and backlash. When those bearings wear, the pinion moves under load, the mesh changes and the unit starts to howl.

Yukon lists the YK GMVET-CI contents as carrier bearings and races, pinion bearings and races, a pinion seal, a complete shim kit, ring gear bolts, a pinion nut, a crush sleeve, thread locker, marking compound with a brush, and a gasket. The bearings and races are Timken. Side yoke seals and side yoke bearings are not on the contents list, so inspect and order those separately.

Symptoms of a worn Corvette differential

• Whine or howl that rises with road speed, louder under power or on decel
• Clunk on throttle changes, from loose pinion preload or excess backlash
• Rumble that changes in long corners, pointing to a side bearing
• Play at the pinion yoke with the driveshaft disconnected
• Oil on the pinion area or the rear crossmember from a hard pinion seal
• Metal in the drained oil or a rough feel when you turn the pinion by hand

How to confirm before ordering

A Corvette rear can make noise from half shaft U-joints, trailing arm bearings, tires and the exhaust, so isolate it first. Our guide on telling transmission noise from differential noise and the carrier bearing noise guide help you narrow it down. With the car on stands, check pinion and side yoke play, drain the oil and look for metal, and record backlash with a dial indicator and magnetic base before teardown.

Fitment

Yukon lists this kit for the 1963-1979 Chevrolet Corvette cast iron differential. That covers the C2 from 1963 through 1967 and the C3 from 1968 through 1979. Later Corvettes use other differentials, and Yukon gives the D36 and D44 Corvette units their own setup rows, so a 1980s car needs a different kit. Because many of these cars have had rear ends swapped over the years, compare your old bearing numbers or the housing casting before ordering, or send us the year and VIN and we will check. Other differential kits are in our rebuild kits category.

Install notes

• Most builders drop the differential out of the car to rebuild it. Mark the side bearing caps before removal so each goes back on its own side.
• Pull old bearings with a bearing separator and puller and drive the new races in fully with a race and seal driver set.
• Use the new crush sleeve. Yukon's chart for the 1963-1979 Corvette lists 14-19 in-lb of pinion preload with new bearings and 6-9 in-lb with used, read with an inch-pound torque wrench.
• Yukon lists backlash of 0.006-0.011 in, 55 ft-lb on the ring gear bolts and 60 ft-lb on the caps for this unit. Check the pattern with the marking compound.
• If the car has Positraction, inspect the clutch plates while it is apart.
• Refill with the gear oil the service manual lists, plus limited-slip additive if the unit has Positraction.

Which Corvettes does this kit fit?

Yukon lists it for 1963-1979 Corvettes with the cast iron differential, which is the C2 and C3 cars through 1979. Later cars use different units and kits.

Are the side yoke seals included?

No. Yukon lists carrier and pinion bearings and races, pinion seal, shims, ring gear bolts, pinion nut, crush sleeve, thread locker, marking compound and gasket. Side yoke seals and bearings are separate.

Can I keep my original ring and pinion?

Yes, if the teeth are free of pitting and chips. Note the original shim thickness, then reset depth, preload and backlash with the new Timken bearings.

Does it work on a Positraction unit?

The bearings and seals are for the differential housing and carrier bearings, so they apply to open and Positraction units. Clutch plates for the Positraction are not included.

Is this a job I can do at home?

With the differential out of the car, a press, bearing puller, race drivers, a dial indicator and an inch-pound torque wrench, an experienced home builder can do it. Setting pinion depth and backlash takes patience and the marking compound.