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      12-19-2012, 04:19 PM   #34
Sered's Avatar

Drives: 08 E90 335i
Join Date: Apr 2012
Location: Melbourne, FL

iTrader: (3)

Originally Posted by robc1976 View Post
This is the part I to not know how to do..."back lash". Did you replace wheel/axle bearings?
The backlash is calculated using a dial indicator and stand. You essentially hold the input shaft in place, and lightly turn one output shaft back and forth (you can feel the ring gear teeth hitting the pinion teeth) to see how much 'play' or 'wiggle room' there is. Backlash measures that wiggle-room. The gear teeth do not ever seat fully, there is a small gap in them. That gap is adjustable using different C-clip arrangements and they vary in thickness. If your stock c-clips don't put it into the correct position (too much gap or too little gap), then you have to buy new c-clips from BMW.

I measured mine and it was .004" dead on in 5 different points before and after the install. The dial indicator and magnetic stand run about $70-80 or so online.

I did not replace my axle bearings or races. They were in outstanding shape.
'08 E90 w/ just boltons
'09 Z4 sDrive35i w/ just boltons