Diff output flange diameter question - 3.46 ratio

[jimbom30cab]

Hi, I've got an e30 medium case 3.46 ratio diff which was originally from a 323i I think.

One of the output shafts is leaking oil so I wanted to order new seals but looks like there are 2 options on the realoem site for 2 diameters of shaft.

I know could remove the drive shaft and slide out the shaft to measure and then order but I kinda wanted to do the job in one go to stop the car from coming off the road for a few days

So just wondered if anyone knows which is the right seal

is it part 3 or 7 ?

http://www.realoem.com/bmw/showparts.do ... g=33&fg=10

thanks

jim

[jimbom30cab]

bumpy

[Brianmoooore]

Obvious thing to do is to pop one of the drive flanges out, and measure the shaft diameter where the seal sits.
Dimensions of the two seem to be considerably different, so no accurate measuring should be needed.