What diff ratio do I have?

[e28jay]

It's an 88 325is Auto. Is it a 3.73 or 4.10? Which e30's came with a 4.10?

[Jordan]

4.10:1 open

[e28jay]

Thanks Jordan!

[M-technik-3]

Climb under and look because you could order optional parts for your car when purchasing it. Just look at the diff tag. Clean the rust off and you'll know for sure or, Jack the car and if one side spins opposite the other it's a open and if both turn the same way it's an LSD.

[reelizmpro]

It's a 3.73LSD.

87-88 325i 3.73only 89-91 325i 3.73 5spd; 4.10 auto.

[Digitalwave]

Barry, his posts said its an auto.

[Erick]

Shouldnt it be 4.10:1 LSD? It's an iS.

[M-technik-3]

Depends on if indvidual personally speced the car with options or depending on what factory had lying around for parts.

[Erick]

But as far as I know, the option for the LSDs were on base "i" models. 325iS's had the LSD standard from factory. Maybe I'm wrong?

[reelizmpro]

Barry, his posts said its an auto.

I know but in 87-88 they only used 3.73 gearing.

[brodee]

I didn't know you could get an "is" with an auto.

[M-technik-3]

I didn't know you could get an "is" with an auto.

Mine was....

[Erick]

I didn't know you could get an "is" with an auto.

oh yeah..... I've seen many 325iS autos. The only cars that were not offered in automagics were 318iS's and M3s

[brodee]

Damn, learn something new every day. Anyway, where is the tag on it so I can check mine?

[Rob]

yup, there should be a metal tag bolted to the diff cover. It will have an S if its an LSD diff, then the gear ratio, which will be self explanatory