98 BD final drive and rear diff ratio

[peter]

Iv been looking into this for a little bit because I am interested in doing a 5 speed swap but if it would be possible to not swap the rear diff to save time that would be great. My car is a 98 2.2 auto bd, I did try to see what I could find on the internet, and one website says all autos were 4.11, a 2.2 manual was 3.90, and a 2.5 manual was 4.11

Is this all correct? Im assuming it is so I could just find a 2.5 manual and not have to worry about changing out the rear diff also. And is there a marking on the rear diff to tell for sure what it is? I took a quick look today but didnt see anything

[mike-tracy]

The best way is to disassemble the rear diff, and count the number of teeth. But if you have the original transmission and diff that came with your car (or compatible replacements), then you do indeed have 4.11 FD.

[elislider]

there are no markings on the rear diffs to discern what it is. the best you can do is mark the input shaft and an output axle and spin the input and see how many times the output rotates. almost 4 times around? then its a 3.9 ratio. slightly more than 4 times? then its a 4.11, almost 4.5 times? then its a 4.44 ....... etc

regarding the transmission, the L models had 3.9 5mts and the GT models (EJ25D) had a 4.11 5mt. you can also look on the side of the transmission next to where the starter is and grab the TYXXXXXXX code and look it up in google and you should find lots of ratio info about that specific transmission.

so if you have a Legacy 2.2 with automatic its (probably) a 4.11 ratio, so you could swap in a 4.11 from a legacy 2.5GT (95-99 models) and then do the necessary auto->manual wiring and be good to go! youll also need the clutch and flywheel as well

[peter]

That's what i was hoping. I'm on the lookout for a wrecked gt now