Well this is a first. I have parked the 2002 for the time being. I thought my load grinding and groaning mouse was coming from the rear wheel bearings. I dropped it off at Black Forest BMW repair to have the wheel bearings changed and got a call that the wheel bearings were fine, if was the rear differential that was grinding and as they put it “howling”. So for now I have parked the car because I don’t want to damage anything else and I don’t want a catastrophic failure on the freeway or something. So I’m now on the hunt for a 3.91 Limited slip differential from a 320i. They used to be easy to find. Now they are getting rare and expensive. The problem with this is that with a 4 speed the freeway cruising RPMs will increase because it’s a shorter gear ratio. Installing the 5 speed will return the cruising RPMs back to normal while providing a shorter gear ratio for gears 1-4. Increasing the performance and responsiveness especially with the cam upgrade that works better at the higher rpm range.
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