Bryan28

So I'm going to say that I am fairly mechanically inclined, as many are on this forum. C5 Getrag differential is more complex and requires special tools. So I made a few of my own. Trying to install motive 3.90's. This is a very low mileage differential. Old Bearings. I have the backlash at .008 thousands but not sure about the test pattern I am getting. Last thing I want is dreaded whine or howl.

Advice needed please!

Bryan

01ssreda4

iTrader: (96)

The compound is too thick, also remember you must hold the ring gear and turn the diff with drag to get a good pattern. Now, from what I can see your pattern is going off the edge of the tooth, and that's not good at all.

Bryan28

Here's after I moved the pinion in 5 thousands. Does this look acceptable?

01ssreda4

iTrader: (96)

It looks better. Id move it some more.

Bryan28

Ended up using a differential shop. 375 in labor ouch. But the pattern was perfect. Gears are silent. They are Motives.

Troy

iTrader: (10)

I agree, the pattern was too high on the tooth. You could've broken one

Bryan28

3.90s with the m12 are plenty low. I love it. After having 2 f body's with 4.10s M6 I just have to have that... breaking them in. Changed the fluid today with valvoline synpower 75w90 and friction modifier. I had them reuse bearings. The housing only had 44k on it. They Looked And Felt perfect.