Another: "What is my diff ratio" Q

[NorthWet]

Well, it is not mine and that is the rub. Coworker, about to spend a small fortune on a used diff that they think that they need. I can't check for the diff tag (not near where I am), and owner says that he can't see one. Local JY says that the only diff they could locate was in Portland, 180 miles away!!! And they want $160!!!!

 

Car is a 93 Impreza sedan with automatic. From what I have determined from searching, it should be a 3.90. Is it really the dirt-common 3.90, or a 4.11, or a something else?

 

Thanks in advance.

Pat

[blackbart]

Drain the oil, remove the back cover, count the teeth on the ring gear, if it has 39 teeth it is a 3.90, if it has 41 teeth it is a 4.11.

I have both and can ship.

[NorthWet]

Drain the oil, remove the back cover, count the teeth on the ring gear, if it has 39 teeth it is a 3.90, if it has 41 teeth it is a 4.11.

...

I can't check ... (not near where I am),

Nice try!

 

And rather than count teeth, I could just look at the number stamped on the ring gear...

 

... but again, not near where I am.

[simbey1982]

The chart i have says the manuals were 4.11

 

http://www.rallispec.com/Transmission%20chart.htm

 

So it would make sense that the auto was 3.9......though when looking up the part numbers it says they are for both AT & MT so its probabally 4.11....my buddy has a used 4.11 he may sell if your interested...Portland also though

 

http://www.subaruparts.com/diag/?model=5&year=1993&style=RS&body=&scn=1&category=195-1