Wheel Speed Sensor in 735i (1985)


Alright so I’m in over my head. A couple months ago I bought a 1985 735i for $300 and have been pouring my paychecks into the car so far and am just getting close to street ready. Then the other day I took a look under the car to see a plug hanging next to the rear diff. The plug is supposed to connect to the back side of the diff but the plug inside the diff itself has sheared off and I can’t really tell how long its been open. I rubbed my finger along the hole in the diff and saw metal shavings and old crust left on my finger and am wondering if this is kind of a death sentence to my differential. Along with this the speedometer hasn’t ever worked and i’m dunno if the two are related. Usually I try to tackle these things on my own but I’m kind of stumped rn and am trying to see if anyone else has any sort of experience with this sensor or any sort of rear diff wheel speed sensor.

I’d pull the cover off the differential and see what’s up inside. At a minimum drain it and take a look at the oil. If that’s a hole directly into the diff, I think it’s toast.

Removing a diff “cover” on a 1985 bmw IRS might be interesting? If 1st step in manual says remove driveline then proceed it could be fun.

Yeah, that’s why I added the ‘drain it’ option.

edit - looks like it has a cover, but I bet it’d be hard to remove while the diff was on the car. Good news, it’s around $900 for the part>