Firstfives.org

If I take out the diff(3:64)in my 76 530i with a 5 speed and put in a diff(3:45) from a 77 530i auto how does it change things in terms of losing or gaining acceleration and also gearing for highway cruising?

You would lose a bit off the line, and at all speeds actually, and drop the revs 150 RPM or so at 100k. With a 4 speed I would want a 3.45, with the 5 speed I'd leave the 3.64 in place. Your speedo will also be off by 5.5%.

Thanks Mike