TCS has successfully set up many differentials that have aided in the performance of our own Pre Runners as well as many other race ready applications. With a TCS Performance differential you can expect many miles of dependable use and increased race ability. Below are a few technical tips from the highly knowledgeable staff here at TCS. Please keep in mind that the proper installation of a differential is key in determining the end result of its all around performance. Although TCS can provide you with many useful technical tips on this type of installation, we highly recommend that this installation be done by a well-experienced professional.

The Differential Adjustments include:
Pinion depth
Pinion bearing preload
Backlash and carrier bearing preload

First Prepare Your Parts
Clean all new and used parts with cleaning solvent, dry parts, use a moderate coat of gear oil on all bearings, and use grease on all seals and seal surfaces.

TCS Assembly Tips
· Both shims go under the pinion bearings. It is best to try using the original shim depth for your first attempt.
· The rear pinion bearing must be pressed on the pinion. We also recommend pressing the races into the housing.
· Mount the ring gear to the carrier with a drop of red Loctite on each bolt. Carrier bearings are pressed on to the carrier.

Check the Pattern
After setting the backlash check the pattern for proper pinion depth. You should brush three of the ring gear teeth with a moderate coat of gear marking compound. The ring gear teeth should be brushed in two different places on the ring gear. Rotate the ring gear past the pinion gear several times and then back so the pattern can be viewed clearly.

Pinion depth is indicated by the location of the pattern between the face and flank of the ring gear teeth. Backlash must be kept within guidelines, and will only slightly affect the pattern between the heel and toe of the ring gear teeth.

Housing alignment and pinion bearing bore alignment can also affect the pattern from heel to toe and can not be corrected without machine work. There are some cases where a precise heel to toe pattern can not be achieved. You can disregard the heel to toe pattern if the backlash is within desired specifications. A contact pattern that is centered from face to flank always indicates the accurate pinion depth even if a pattern that is centered from heel to toe can not be achieved. If the contact pattern is towards the face of the ring gear teeth then the pinion is too far away from the ring gear. Adjust the pinion shims to move the pinion gear towards the ring gear centerline. The pinion is too close to the ring gear if the contact pattern is towards the flank of the ring gear teeth. You can adjust the pinion shims to move the pinion gear away from the ring gear.

If you are changing the pinion depth, make large changes (0.005" to 0.015") until the desired pattern is achieved. By making adjustments that move the pinion too far, you can determine that the correct pattern is somewhere between the two extremes. Make smaller changes (0.002" to 0.004") until the pattern is centered between the face and the flank of the ring gear teeth. When setting up a used ring & pinion, pay more attention to the pattern on the coast side of the ring gear teeth and pay less attention to the drive side.

Gear Oil, Additive and Break-In
TCS recommends GFO85140 weight gear oil by Quick Change Exchange.

Use a gasket or 100% silicone to seal the cover or third member to the housing. Fill the differential to drain plug level until the oil spills out the plug-hole.

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For Tech Support or Questions Call:
928-453-4020

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