Install 3.23 Differential

Summary

Install a 3.23 Limited Slip Differential to increase top speed.

Start Date: July 18, 2012

Odometer: 309,000 km

Total cost: $2

After replacing my failed M50 engine and transmission, I drove my car and discovered that the gear ratio of the existing 4.10 Limited Slip Differential was causing the car to hit the RPM red line at approximately 140km/h in 5th gear. Average track speeds at the tracks I drive are in the range of 160km/h to 220km/h, so the 4.10 differential was completely unusable. I decided to replace it with a 3.23 LSD from a 2000 M Roadster that had been on my previous E30.

Parts

Journal

Changing the differential oil (it's easier to remove all old oil with the differential out of the car). Installed new drain plug gasket rings (washers) to prevent leaks.

Part number label:

Lowering the old differential out of the car (drive shaft and rear axles removed):

New differential installed: