so I was driving downtown to get a haircut and I hear a bang followed by my car refusing to engage in any gear. So I coasted/rolled to a safe spot and inspected the car.
This is what I found:
my 3.23 M3 diff (installed by me a few months back), broken mounting point
output shaft, with a few bolts backed out, others bent/stretched.
I think what happened was that a couple bolts on the output shaft backed out and then the rest get over stressed and forced their way out. Once the output shaft was disconnected, the diff tried to pull towards the other side and snapped the mounting point.
I did torque the bolts connecting the output shaft when I installed the diff a few months back, but I didn’t locktite them.
the questions:
is my analyst reasonable / correct?
can I swap the guts of this diff into my factory non-LSD diff (or do I need a whole new LSD?)
what other damage might have been caused (drive shaft?)
if I remove the messed up bolts from the output shaft, it is safe to use again with new bolts?
You should be able to buy the rear cover for the diff (P/N 33111213046 ?). Maybe you can get a shop (Fleet Pride?) to cut the bolts flush on the drive shaft and back them out. You might need a new output flange - depending on how mangled yours is.
I don’t see why I can’t cut the remaining bolts and just pull them through… I don’t believe anything is threaded in the output shaft, only in the side of the diff.
after some more research, in theory I can swap the rear cover from my stock diff along with one of the OEM sides to the output shaft. Then I need to inspect and possibly rebuild the output shaft (there is a kit for this). If all goes well this won’t cost too much.
if an E46 diff would work, i have one on the floor in the shop that has some gear noise to keep you on the street you can borrow. it’s out of a 330, so it’s a tall ratio non LSD.
clean threads, and loctite is a good CYA too… Porsche axles are notorious for coming loose after service, and new bolts are typically a good idea for them.
