Quality Differential Parts since 1982!


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Free Technical Support West Coast Differentials offers Free Technical Support before and after you buy differential parts from us. Our differential parts experts will make sure you get the right parts the first time!
Same Day Shipping At West Coast Differentials we think you deserve to have your parts as soon as possible. So most orders placed before 4pm Pacific time ship the same day!
Differential Parts Distributor We have your differential parts in stock ready to ship today. West Coast Differentials stocks a complete line of light duty axle parts for Chevrolet, Chrysler, Dana, Ford, GM, Jeep and Toyota axle assemblies.
We Make the Difference At West Coast Differentials we are committed to making your experience with us totally enjoyable. We think top notch customer service is the most important thing we do. Hence, at West Coast Differentials, We Make the Difference is much more than a slogan.

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Eaton Detroit Truetrac FAQ’s

Eaton Detroit Truetrac FAQ’s

What kind of oil should I use? Can I use synthetic? Do I need friction additive/modifier? A quality petroleum/mineral based oil works best in the Truetrac units. We do not recommend synthetic oil. Friction additive/modifier is not required.

Can I use the stock bearings? In most cases the Detroit Truetrac units work with the factory (stock) bearings. The exceptions are: 10 bolt 8.5\8.6 GM axles, the “Performance” Dana 35 & 44 and GM12 bolt with 35 spline axles. No other “special” setup is required.
What kind of break-in is required? The Truetrac units do not require a break in. The unit’s internals will take a little time (depending on driving conditions) to “seat.” Afterwards there will be a slight improvement in its performance.

When does the Truetrac lock up? The Truetrac is a helical gear limited slip differential and never “locks up”. The Truetrac operates by transferring power from the spinning wheel to the wheel with the most traction. If one tire breaks traction, the amount of rotation (or spin) is controlled. The torque is then sent to the other tire that still has traction.

I use my car on the street and on the strip, will the Truetrac hold up? On the street, the operation of the Truetrac will be transparent. You will not know it is there until you need it. In racing situations the unit will apply torque to both tires and launch straight as an arrow, time after time.

How much horsepower and torque will the Truetrac take? There are many factors to consider when determining if a specific differential will last in your vehicle. Horsepower and torque are important factors. However, the weight of the car, tire height/width, the terrain and suspension are all important things to take into consideration. For example, a setup that uses street tires will live longer because both tires will break loose and spin before any real strain is put on the unit. But as the tire gets wider, the stress on the unit increases because the traction is greater. When in doubt, the best bet is to call us with your specific application and driving conditions.

Can Truetrac be used in the front axles of full time 4 wheel drive jeeps and trucks? Yes, it can. You will find will find Truetrac differentials to be very smooth yet effective in either end of your vehicle.

Can I repair the Truetrac if I need to? The worm gears inside a Trutrac are maintenance free, and do not require regular service. Internal failure usually results in the damage of the worm gear pockets. Therefore, they are not rebuildable.

What is the warranty? The Detroit Truetrac unit is covered for one year from date of purchase against defects in materials and workmanship up to a 38.”

Application Guides

Differential Parts Application Guide See the parts that are available for your vehicle, with direct links to our most current parts catalog.

Tech Topics

Differential Repair-Gear Ratio Calculators-setup specs-installation Instructions

Tech Topics include everything from Differential Identification to Installation Instructions and New Gear Break-In Procedure

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Order Parts

Our LIVE Differential Parts Experts are ready to take your call Monday thru Friday from 8AM to 5PM.

(800) 510-0950

Most orders received before 4PM Pacific Standard Time will be shipped out the SAME DAY, with next day delivery via ground service to most of the West Coast!

We do not offer Online Ordering We want to make sure you get the right parts... Simply give us a call! Let our parts specialists take the guesswork out of your order.

Parts Catalog

The most current listings can be accessed using the "Find Your Parts" link (Look for the magnifying glass!)