can you put a different diff in a ix?

[Killacortes]

i own a 89ix and i think it came with a viscous coupling 3.91. i was wondering if thats the only option or can you put something else in there? my thinking was a different diff for gas mileage or does that not even help with mpg?

[spdracrm3]

only other option is 4.10 diffs out of auto's which will be worse gas mileage wise,faster acceleration.
they did make 3.64's in europe that would help with mileage a bit ,they are a bit difficult to find and ship but can be done ... they are getting hard to find over there too

[e30trooper]

im not sure about e30 ix's but with impreza's you can't swap the diff unless you change the matching trans/axle since they are AWD alltime. You will break parts.

[nando]

ix's don't have a transaxle, but both front and rear diffs have to match.

your easy options are 3.91 and 4.10. harder are 3.64's (early euro manuals), and nearly impossible to find are 3.73's (early euro autos). I've never seen a 3.73.

[z31maniac]

^Are the gearsets between viscous/clutch LSD's different?

In other words, if a guy wanted to, could he throw a 3.73 R&P from a clutch LSD in a VLSD case?

[nando]

rears are the same but you still need a matching gearset for the front.