MCoupe diff cover... leaks?

#1

My buddy (a career BMW tech/foreman) and I installed 2 MCoupe diff covers on two E30 pumpkins, and both of them are leaking when driven hard. We can’t tell where the leaks are sourced (i.e.- they are just soaked). Indeed, we used fresh gaskets and the appropriate (we think) hardware to bolt it all together. We are using new-style drain plugs which have the integral rubber seal. Everything is torqued properly.

Anyone else experienced anything like this after retrofitting the MCoupe diff cover?

TIA.

#2

Matt,

If I am not mistaken, Carter has a finned diff cover on his Korman rebuilt diff. I don’t think he has had any issues with it. You might call him or even try Korman to see if they have any ideas.

  • Ken
#3

I put one on mine, I know there were at least two longer bolts that were required and I ‘think’ a different gasket.

No leaks on mine.

#4

Cobetto has one as well and after 2 seasons I have not seen a leak there.( I have adjusted the rear sway several times and got an up close look)

#5

check the speedo sensor o-ring (I had the same problem, almost drove me nuts trying to find), they won’t leak on the old dif cover but when you pull it out and try to reuse it they never seem to fully seal again (it’ll be rock hard and probably cracked a little if you look at it closely), its like a .60 part from the dealer, real OEM has the part number.

I’ve tried matching it up with one from MCmaster-Carr didn’t have much luck,

Also I’ve resorted to just RTV’ing the dif cover to the dif, I’ve never been happy with that cheap paper gasket they use. Never had leak issues this way