Install a Limited-Slip Differential

Also packaged with the rear gears are a large number of shims in varying thicknesses. They go between the carrier bearings and the axlehousing. By varying the shim thickness, the carrier is moved left or right in the housing. This adjusts the depth of the mesh between ring-and-pinion gears. How and where the ring-and-pinion mate is vital to avoiding siren-like gear noise.

DriveTrain Direct is a rear-axle specialist, so it has all the trick tools for removing and pressing on bearings, measuring pinion depth, and so on. Here the carrier bearings are being pulled off our old carrier before being transferred to the new Traction-Lok carrier.

Putting the ring gear on the carrier is super easy--just bolt it on and gun the bolts to eye-watering tightness. The bolts are supplied with the overhaul kit, or if you're working in the field, you can reuse the bolts in your existing carrier.

Pinion-seal leaks are a chronic differential condition, it seems, so DriveTrain replaces them with the gear change. Here Martin knocks the old seal out using a removal tool. The installation can be done with a large socket and some skill, but a seal driver is faster and easier.

Our pinion bearing shows signs of fatigue that Martin doesn't like. They were light streak marks on the bearing's rollers, but enough for Martin to reach for a new bearing and race. Here he presses the new bearing onto the pinion shaft--one operation where he really does prefer the press.

Strange as it sounds, Martin says another source of differential leaks is through the pinion and flange splines. Thus, he always gobs silicone sealer on the female splines to ensure an oil-tight connection.

Gunning on the pinion flange puts the squeeze on the crush sleeve. Martin will next check the pinion drag by hand (there is a definite tightness, or drag, on a properly installed pinion). This shot shows that with a universal between the gun and socket, there is room past the torque arm to get the job done. Pinion depth is set using shims and checked with a dial indicator. Refitting the same thickness that came out usually gets you close enough.

You really don't want to watch your carrier assembly going into the axlehousing. Martin selects a set of shims based on what came out of the axle, fits them to the carrier's side bearings, offers up the carrier to the axlehousing, and drives it home with a few good whacks from his dead-blow hammer. Somehow the ring-and-pinion gears find each other and sort themselves out without damage.

Once the pinion depth has been correctly set, the last critical part of setting up the gear set is getting the carrier (ring gear) correctly positioned left-to-right relative to the pinion gear. This is done by both witnessing the pattern the gears make and having approximately 0.010 inch of backlash (play) between the ring-and-pinion gears. The dial indicator measures the backlash, while the greased area makes the contact area visible.

Adjusting the ring gear left to right is done with precision-thickness shims. While the thickness is marked on the shims, Martin finds it quicker to measure the shims with calipers. This also provides a double-check of the true shim thickness.

Rotating the greased area once through the pinion gear reveals the contact pattern. The pattern should be centered laterally and vertically on the gear teeth as shown here. The pros take a couple of tries with different shims to get this pattern. If you try this yourself, you may find it takes a little longer.

Martin knocks a new set of wheel bearings onto brand-new, 31-spline Superior axles for us. We need only new axles because the PowerTrax that was in the 8.8-inch before required slightly shorter axles, and thus they would have floated sideways a bit with the Traction-Lok. That actually would have functioned fine, but would have caused a clunk in the corners.

With the axles in the housing, the C-clips, the cross-shaft, and the retaining bolt go in. For road-course work, C-clips are the preferred axle-retention method, unlike drag racing. That's because snapping the axle due to excessive torque is not an issue on road circuits, but retaining the axle under high cornering loads is.

Topping off the axle with gear fluid and reinstalling the Maximum suspension parts finishes the installation. Aside from light tire scuff in tight turning maneuvers (parking lots and 90-degree intersection turns), the Traction-Lok does its job without fuss. 5.0