MY automatic gearbox ratios

Post by **TOONGA** » Mon Oct 12, 2009 8:36 pm

just a quick question concerning MY automatic gearbox ratios

if the front diff ratio is 3.7 is the rear diff ratio 3.7 or 3.9

three reasons

1. my friends diff has no ratio written on it

2. the subaru service manual puts it at 3.9 GREGORYS makes no mention at all

3. he is putting a manual box into his car with a 3.7 ratio

thanks

TOONGA

Gannon · Post by **Gannon** » Mon Oct 12, 2009 9:12 pm

Take the back cover off, and count the teeth on the crownwheel.

37 will make it a 3.7:1, 39 will make it a 3.9:1

steptoe · Post by **steptoe** » Mon Oct 12, 2009 10:15 pm

I like how you say "if" the front ratio is 3.7:1

In my L Series 4WD auto the front diff ratio was 3.45:1 with the rear at 3.7:1

Bit of a mind boggle to work out how it coped. It had a back (as in esrever) cancel relay to cut out the rears when in R, and it certainly did not like tight turns on the dirt in 4WD.

Have shoved in my 5 speed manual D/R box since and love it, lucky it was a 3.7:1 front diff to match the rear. I do miss the added 4WD traction in the wet from the auto though.

Toonga, your mate will still be able to drive it in FWD until he gets right diff ratio. Not heard of anytrhing but 3.7's in MY

phillatdarwin · Post by **phillatdarwin** » Mon Oct 12, 2009 10:42 pm

Suparoo wrote:Take the back cover off, and count the teeth on the crownwheel.

37 will make it a 3.7:1, 39 will make it a 3.9:1

undo the bung in the bottom bung dran the oil out undo the top bung at the back .
mark with a white pen and do the same as quote
.