T series diff ratio

**el corona** · 29-07-2009, 11:49 PM

Hi all, my RT132 corona 'manual' is fitted with a T series diff from factory. Ive been trying to find information on the ratio's of the diff and was wondering if i have a 3:9 ratio? Did the auto ones come with 4:11? Reason i am asking is the backlash in m diff is pretty damn bad and the seals are starting to leak so im basicly looking for a replacement.I was considering using the LSD ones from the AE86 but dont know if i have to mod my diveline to fit it. What can i do with my problem?

**white_sandshoe** · 30-07-2009, 12:36 AM

http://akb.norbie.net/Public/AxleCode.aspx

have a look on your compliance plate next to where it says Trans/Axle
there should be a code next to it that says something along the lines of T312 or T292
Punch that code into the translator in the above link, and rock and roll!

I'd suspect it's likely to be a T312, making it a 3.9:1, but could be anywhere from a T302 (3.73:1) to a T292 (4.1:1)

**el corona** · 30-07-2009, 10:30 PM

checked my car just then, its says T312 so it was 3:9. So if i go to the wreakers and find a auto one, would the ratios be 4:11?

**old_school_jap1** · 31-07-2009, 12:28 AM

toyota didn't always change it's diff ratios between auto and manual. go to the wreckers and find a toyota with t292 on the plate in the same place your corona had t312 written. ta22, ta23, ra23, ra28, ra40 celicas all had the 4.1:1 (t292) centre that you want

**RobertoX** · 31-07-2009, 12:35 AM

Look for an auto RA40... I always find a t292 in these and they are plentiful at wreckers

**el corona** · 31-07-2009, 05:28 PM

does anyone have any experience with a 3t-gte -w55 box using 4:11 diff? what revs does it hold at 100kmph?

**thanhngo** · 03-08-2009, 11:16 AM

Rather than hijack, I had a similar question.

Are crown and pinions interchangable between same sized diffs - can you mix and match? e.g. say you had a 41 / 9 (4.5), can you just get a 43 crown gear and use it with the 9 tooth pinion on the 4.5? Or are CP paired and you can swap different gears to make combos?

**sbfoot** · 03-08-2009, 02:47 PM

Crown wheels and Pinions are paired and won't work when mixed and matched.
Scott

**"Z" UTE** · 02-07-2015, 01:57 PM

Originally Posted by thanhngo

Rather than hijack, I had a similar question.

Are crown and pinions interchangable between same sized diffs - can you mix and match? e.g. say you had a 41 / 9 (4.5), can you just get a 43 crown gear and use it with the 9 tooth pinion on the 4.5? Or are CP paired and you can swap different gears to make combos?

To add to what Scott has said. For a given diameter diff housing only a certain diameter crown wheel will fit. If you want more teeth on the crown wheel you have to decrease the tooth size, that then changes the size and pitch of the teeth on the pinion. Meshing different CW and P's would be like fitting a Metric bolt with an Imperial nut! The other reason for not trying to swap them even when swapping like for like, is that the CW and P are lapped together at the factory to ensure best mesh. Then of course you have the black art (Shims and Prussian Blue) of getting the mesh correct when you actually install the set into the housing.

cheers Chuck.