Boom.

[Motorsport3]

I was having an awesome Monday until I blew up my diff. Yep.... shifted into 2nd and BOOOM from the rear... no more go. Can anyone give me an idea of what has occured and if it's repairable? I'm trying to get my game plan together.

Thanks.

[MartyBtoo]

If it went boom and then nothing I'd say it is more likely to be driveshaft oriented. Differential problems tend to sound like you threw marbles in a blender when there are gear issues, and an axle would still move some with one wheel driving.

Marty

[rf900rkw]

Get it in the air and see what went boom. It could be as simple as a stub axle pulling out of the diff. And if there wasn't a lot of preceding noise, that is the most likely item.


Does the Speedo still read? If so, it's an axle issue; downstream of the diff.

[Motorsport3]

The speedo moves a little bit. If I rev to 4 grand or so, it'll barely go past the first couple of marks.

[rf900rkw]

Ooops. Any noises?

Time to crawl underneath and see where the disconnect is. Stick the trans in gear, and turn the tires by hand. Where ever the motion stops is your broken component.

Engine off, of course.

[Motorsport3]

No grinding / crunchy noise. I just put it in gear, engage the clutch and hear "spining" noise... like the pinion shaft has broken clean in half.

[rf900rkw]

Well snapping the pinion would be a feat not even Mindy has accomplished. Yet, anyway.


The two most likely places would be the axle shaft or the clutch itself. A broken or pulled axle would have the speedo registering normal road speeds. The whirring noise suggests something downstream of the clutch is turning. Weird stuff. Transmissions, driveshafts, and diff's don't just pop.

[PbFut]

do not attempt to apply engine power until you figure out the problem or further damage may result. Half shaft issues are beginning to show up more and more. Ring a pinion issues are rare unless incorrectly repaired or modified. Good luck

[QuestMCoupe]

Sounds like a rear axle to me. When one of mine went out years ago, my car had the exact same symptoms. This was so long ago that it was still covered under warranty.

[CMM3]

Check you axle flange first it could have simple popped out.
What you're describing sounds exactly like what was happening to my car until I took drastic measures to fix it permanently.
If you see one flange sticking out from the diff more than the other then that's your problem.
You can just push it back into place for a temporary fix.
See this post on what I ended up doing.

http://forums.bimmerforums.com/forum...tion-Hopefully

[lokijibber]

So many guesses/possibilities, but you could probably identify the issue in 5 minutes under the car. I'll guess an exploded guibo (forgive me for not remembering the correct spelling Ben)

[Motorsport3]

CMM3 FTW. Driver side axle flange popped out.

[rf900rkw]

Then the speedo DID read and I'll stand by my first thing.

[Motorsport3]

It didn't read normally but it did move so I'll give you some of the props.

[CMM3]

I had two sets of spacers made up at different thickness 1/8" and 1/4" and bought the longer bolts to go with each.
When the first 1/8" set I installed did the trick I didn't use the second

So I still have the 1/4" spacers = 6.35mm.
If you read the thread I provided you'll see that Porsche inner CV's can be substituted which is the same as adding an 8mm spacer.
So the thickness is known to be OK.

I also have 12 each BMW longer torx bolts to be used with them.

If you'd like this kit I'll set it to you for $100 shipped, pretty much my cost to have the spacers made/machined and buy the bolt.
It will take out the excess slack or play in the system and help relieve the pulling force being exerted on the flange, and there is no disadvantage I know to installing it.

Pictures of kit below

[Motorsport3]

PM'ed

[z3papa]

I had this exact thing happen this weekend. After a brief period of speculation, a guy on course said a part from my car was still at his work station. Walked out and it quickly led me to examine the driver's side half shaft which was easily inspected since we pushed the car onto a trailer. The cage where the shaft bolts to the diff. was fubar big time. At least it appears it wasn't the differential. Will report once we get a replacement in tomorrow night whether there is anything else at issue.