Rear Diff

caboolture · Post by **caboolture** » Sat Jan 31, 2009 12:22 am

Ok here is the plan for a 91 liberty transplant. 92 RS turbo motor with 91 dual range gearbox with a 4:11 diff or 3:9 diff. What i would like to know is the difference. It will be used mainly for on road use. Cheers Peter

Matatak · Post by **Matatak** » Sat Jan 31, 2009 1:34 am

the rear diff will have to match the box. (which id say is more than likely going to be 3.9 if a manual DR)

so you cant just choose what diff you want to use as it wont like it if its not suited to the box.

discopotato03 · Post by **discopotato03** » Sat Jan 31, 2009 8:07 am

I look at most of these Nissan and Subaru final drive ratios as being approximately 5% gaps .

If you multiply 3.9 by 1.05 you get 4.095 . If you divide 4.111 by 3.9 you get 1.054 .

A .

brumbyrunner · Post by **brumbyrunner** » Sat Jan 31, 2009 10:33 am

When you're caculating gearing you need to look at the gearbox ratios as well as the diff ratio. I've mixed and matched to get the lowest possible gearing from factory ratios but for your application, you might not want that.
Are you happy with your gearing now? Unless it's been changed you will have:
1st 3.545
2nd 2.111
3rd 1.448
4th 1.088
5th 0.871
Diff 3.9:1
Low 1.196:1

AlpineRaven · Post by **AlpineRaven** » Mon Feb 02, 2009 8:58 pm

It would be 3.9 if its gen1 D/R box. if it was automatic it would be 4.11
Cheers
AP