Buying Advice for 318i with Suspected Bad Diff

[Chuckles]

Hello,

I am going to look at a promising 1991 318i on Wednesday that I may get for a reasonably low price because the owner feels the diff is shot. According to him he was driving along when he started to hear clunking/banging noises so he parked the car. I wish I could provide more of a description, but this is all I got. I would appreciate input on the following questions:

- Do the small case diffs typically fail?

- Could this be bad rear sub/diff bushings?

- Any other thing I should look for?


Right now I am thinking about changing out the diff fluid and seeing if that helps, but it is common for fluid to eventually leak out?


Thanks,
Chris

[ArtClassShank]

Does it still drive?

[Chuckles]

According to the owner it "should" make the half-hour drive back to my place. I have roadside assistance so I have also debated about getting it towed to my place if it is possible the diff is salvageable. However, I have been searching for a 4.10 LSD as backup.

I have been seeing conflicting info about small case and medium case diff compatibility. Can anyone viewing also verify whether a medium case diff is a direct swap (1991 M42) without any other parts/hardware?

[jlevie]

That sounds more like a bad drive shaft or half shaft than the differential.

[cunninglinguist]

Check the center support bearing on the driveshaft.

[Chuckles]

My visit got postponed until tomorrow, but I will check the CSB & driveshaft components. Owner appears to be certain it is the diff. Nonetheless, the diff was on my list of updating since LSD > open.

[ArtClassShank]

My visit got postponed until tomorrow, but I will check the CSB & driveshaft components. Owner appears to be certain it is the diff. Nonetheless, the diff was on my list of updating since LSD > open.

Well if it is the diff, you can get tons on here for $200 or less.

[Chuckles]

Didn't go for it. Not only was the new paint job (< 1yr) showing rust it was only running on 3-cylinders. These multiple commutes for misrepresented cars are becoming annoying.

[Dakotademon7]

Didn't go for it. Not only was the new paint job (< 1yr) showing rust it was only running on 3-cylinders. These multiple commutes for misrepresented cars are becoming annoying.

No one ever wants to say there car is a turd. It used to be fun to buy and sell but it's getting to be to much BS anymore. CL is the biggest PITA.