Something's broken

[alexk]

I guess you are talking about the front bolt (?).

BMW has new bolts for the diff cover (2 bolts).
Here you can see the difference, the new bolt is not threaded all the way.
The old bolts would break.



You could look at a damaged E46 M3 diff and then swap the casing.
It's not very difficult to do.

[Jimbo]

Originally Posted by alexk

I guess you are talking about the front bolt (?).

BMW has new bolts for the diff cover (2 bolts).
Here you can see the difference, the new bolt is not threaded all the way.
The old bolts would break.

Apparently, of the 3 bolts that hold it in, 2 at the back are ok, its the one 'at the side' that failed. And were threaded half way down, so the new style ones by the looks of it.

BMW have since come back with “ due to the age were unable to offer any financial assistance towards the cost of this repair”

[alexk]

Originally Posted by Jimbo

Apparently, of the 3 bolts that hold it in, 2 at the back are ok, its the one 'at the side' that failed. And were threaded half way down, so the new style ones by the looks of it.

BMW have since come back with “ due to the age were unable to offer any financial assistance towards the cost of this repair”

Sorry to hear that mate.
It's better if you find a damaged diff and you swap the cases.

[karbonkid]

Any pics of damage? Could helicoil. I have a kit here. They're in-expensive.

CSL Diff on eBay. Been up for a while and been reduced once before. Im sure he will take an offer. £300?
http://www.ebay.co.uk/itm/BMW-M3-CSL...item4ac15f5dac

[Equinox]

Diff bolts sheering was a very common problem on E36 M3's but ive never heard of it on an E46 before.

[shane@mbtech]

Im sure I have a casing here. If you are interested in the casing let me know.

Likely overtightened has caused it and stretched the bolt.

[shane@mbtech]

Originally Posted by karbonkid

Any pics of damage? Could helicoil. I have a kit here. They're in-expensive.

CSL Diff on eBay. Been up for a while and been reduced once before. Im sure he will take an offer. £300?
http://www.ebay.co.uk/itm/BMW-M3-CSL...item4ac15f5dac

That diff has been opened very recently, with no mention in the advert.

The bolts are like new and the rear casing is extremely clean.

[Neil M]

Originally Posted by lawsy

Likely overtightened has caused it and stretched the bolt.

I'm inclined to agree with lawsy (that's a first) the bolts have been overtightened, usually the sign of a pneumatic socket having been used to fit them and not a torque wrench.
There's a lesson to be learned there, just unfortunate that it's at your expense.

[Jimbo]

Thanks for the advice guys, hopefully some warnings for others as you say. Just a pity BMW don't want to play...maybe i should pick it up with them in Munich.....if i wasn't going to spend all my cash on getting this fixed.

Current plan is to use a local engineering firm to re-helicoil the diff casing mount (its only done 30k). If i can get a decent price on the labour as i also would like them to do an Insp 2, an exhaust hanger, check the subframe and do any repair/precaution on the back of what they find, hopefully what i have read regarding goodwill on the subframe will hold true.

[shane@mbtech]

Originally Posted by Jimbo

Thanks for the advice guys, hopefully some warnings for others as you say. Just a pity BMW don't want to play...maybe i should pick it up with them in Munich.....if i wasn't going to spend all my cash on getting this fixed.

Current plan is to use a local engineering firm to re-helicoil the diff casing mount (its only done 30k). If i can get a decent price on the labour as i also would like them to do an Insp 2, an exhaust hanger, check the subframe and do any repair/precaution on the back of what they find, hopefully what i have read regarding goodwill on the subframe will hold true.

It dont take too long to get diff out. Not a big job.