BMW Z3 Rear Differential Gear Ratio Change and Rebuild

In this sweat session I tackle the final step of my manual swap, the rear differential gear ratio change. The 2.8 Z3 auto came with a 4.10 gear set while the manual cars came with a 3.15 ratio. It drove fine with the 4.10 but 1st gear was generally useless and highway cruising had the engine operating in the 3k rpm range for 60mph which can affect fuel economy. This was challenging and did require some special tools like torque wrenches and a press, however, not impossible.
Please see the page on the following link as it is really good technical/comprehensive guide to this entire process.
www.bimmerforu...
Here is the rebuild kit from Ireland Engineering that I used.
www.iemotorspo...
Here is more good information on the BMW differentials.
metricmechanic...