legacycentral bbs

i have a bearing that has gone out on my rear diff and i was contemplating getting a salvaged diff instead of the bearing itself. i have a 4.11 diff right now and i was wondering what sort of handleing differences it would make to put a 3.9 on instead.

im sure someone will correct me if im wrong, which i very well could be, a 4.11 is a low geared diff and a 3.9 is a high geared diff. so in theory if i put a 3.9 on mine instead wouldnt the rear get more power transfered to it at say highway speeds and such and the front be favored intown driving? (or vise versa) that would be the only major change i could see happening. the only reason i wondered was in case a 3.9 was all i could find.

The diff ratio in the rear must match the ratio in the front diff (inside the trans). So unless you are changing the trans as well you have to stick with the 4.11.

Gary

5MT or 4EAT? if its a 5mt your center differential will like shoot itself in the head after a very short distance
4EAT i bet you could keep going, but your clutch pack would be screaming and roaring and maybe smoking, untill they weld themselves together

i actually have no idea what happens, but i know that there is nothing good that can come of doing this

i was wonderin if they had to match or not also. i was thinkin about that on my way to work and id bet teh same goes for limited slip also.

yes its a 5mt (like it says in my sig)

thanks either way.

they have to match. In some model years, the center diff wasnot always 1:1. In which cases the ratio in the rear, does not match the ratio in the front, but due to the difference in center ratio's they balance out. The best way to find out what years match, is to call your friendly local dealership parts guy and see if he has enough time to navigate the subaru parts lookup program and find out all the ratios for you. When you get into switching parts of a drivetrain, there are lots of factor to consider. It's generally easier to convert to an entire system.