Installing the Detroit SoftLocker in a Toyota 8" Differential

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Author: Joe Micciche March 2000

The Detroit SoftLocker replaces the stock open carrier, and provides 100% lockup of the axles.

I had been driving and wheeling my Toyota the last several years with a stock rear open differential and a Detroit TrueTrac limited slip (LSD) in the front. Like all 4-wheelers, I was very aware of the benefits of a rear locker for offroad performance, but I had been a bit gun-shy about installing a locker in the rear axle due to the slippery roads during our harsh Cleveland winters. Cost and complexity prevented me from installing a manually-activated locker. I held out 'til I couldn't take it any longer, and decided to buy a Detroit SoftLocker.

Tractech, manufacturer of the Detroit line of traction aiding devices, has been producing the improved SoftLocker for the Toyota V6 8" (and other differentials) for several years now. Improved refers to the lack of ratcheting noise off and onroad. This locker virtually eliminates the clicking and banging associated with the Detroit Locker and other automatic lockers, while providing 100% lockup side-to-side. The SoftLocker replaces the entire stock open carrier, which is one of the reasons it is stronger than simply replacing the spider and side gears. For me the strength, coupled with ease of installation and maintenance (no electrical or air assemblies, and no special additives) was particularly appealing.

Installing the Detroit SoftLocker

The wheels are off, the brake lines removed, and the brake and axle assembly is removed from the housing.

After receiving the Toyota V6 8" SoftLocker and installation kit from Essentially Offroad, I headed over to Peters Offroad to have Matt Peters do the installation.

First the wheel lug nuts were loosened, and the rear end was jacked up and jack stands placed under the frame rails. The wheels were removed, and the gear oil was drained from the differential.

Matt wrapped a towel around the rear main brake line, then clamped it with vise-grips to minimize loss of brake fluid. The brake lines were removed from each rear wheel, and the emergency brake cable was disconnected from the parking brake levers coming through each backing plate.

There are four 14mm nuts holding the bearing/brake assembly to the axle housing. These were removed from each side, and Matt grabbed the brake assembly and pulled the axle shaft out of the carrier and tube. The shafts and splines looked to be in excellent condition.

The housing, with everything removed, should get a good cleaning.

My truck is equipped with rear-wheel ABS, so next the ABS sensor was removed from the differential housing.

Matt then marked the driveshaft in relation to the differential flange so it could be reassembled in the same position it had been in. The four bolts on the flange were removed, and the driveshaft was secured up and out of the way.

The ten 12mm nuts holding the differential case to the axle housing studs were removed, and the differential assembly was pulled from the housing.

The entire housing is placed in a vise, ready to be torn down. The adjusting nut retainers are removed from the bearing cap, then the bearing caps are removed.

Matt then began tearing down the ring gear and carrier. First, the carrier bearing caps were clearly marked to ensure they would be installed in the same position. He then removed the backlash adjusting nut retainers, and removed the bearing caps. Then the carrier assembly was removed from the housing.

The stock carrier in a vise, lock plate tabs flattened, ready to remove the ring gear.

The ring gear bolt lock plate tabs were flattened so the bolts could be removed. Once the bolts were removed, Matt tapped around the ring gear with a brass drift to separate it from the carrier.

The old gasket material was removed from the housing, and everything was inspected prior to reassembly. Here again, all parts looked to be in excellent condition, with the ring and pinion showing no abnormal wear pattern. This was good news after 88,000 miles of use!

The new carrier bearings are pressed on.

Next, Matt seated the ring gear on the Detroit. The lock plates were put in position, the ring gear bolts were started, and he worked around the new carrier gradually tightening down each bolt to the Toyota-specified 71 ft. lbs. of torque. Once torqued, the lock plate tabs were reset around the ring gear bolts.

The new carrier bearings were then pressed on to the locker.

The Detroit ready for reassembly, with the ring gear on, and new carrier bearings. Backlash is checked upon reassembly, and again after everything is torqued down. Once everything is torqued, Matt checks the gear pattern.

The differential was then reassembled to the housing. The carrier was seated in the housing with the new bearing races in place, the adjusting nuts were put on, and the carrier bearing caps were put in place. Matt tightened the bearing caps, hand-tightened the adjusting nuts, and checked backlash with a dial indicator. He adjusted the backlash until it matched the Toyota specification of 0.007 to 0.008 inch. The bearing caps were then torqued down to 58 ft. lbs., and checked the backlash again. The setting was still within spec, so the adjusting nut retainers were put in place.

As a final check, the gear pattern was examined. Marking compound was put on the ring gear, and the pinion rotated with a socket on the pinion nut. After ensuring he could read the pattern, Matt checked it and found it was acceptable on the first attempt! The differential was ready to be put back in the axle housing.

Reassembly and Testing

Sliding the axle shafts back into the tubes, taking care not to damage the outer axle seal.
Here's the complete differential with locker, ready to bolt back into place.

Reassembly was rather quick and straightforward. First, silicone was used on the surface of the axle housing where the differential would be placed. The differential was then seated, easily guided by the mounting studs. The ten 12mm nuts could then be torqued down. Next the driveshaft was reinstalled (using the matchmarks made during removal). With that completed, the axle assemblies were put into the axle housing, and the four 14mm nuts tightened down. The emergency brake cables were reattached to the parking brake levers, and the brake lines were threaded into the cylinder. After bleeding the rear brakes, the tires were put back, the differential was refilled with gear oil, and it was all ready for a test.

We performed a quick test before hitting the street: we securely chocked the front tires and placed the vehicle in neutral. With the rear tires off the ground, we rotated one tire until we heard the locker click. We then rotated the tire in the opposite direction, and found the tire on the other side turning in the same direction. So it was all ready to drive.




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