Hi all,
A bit of a back story - I got my e30 a couple of years ago in the auction. The previous owner swapped M40 and 5 speed to M10 carb and 4 peed from what I believe was from E21. The car still had the same original 4.27 diff in it when I got it. It was impossible to drive it above 70km/h as revs were at about 4500rpm. I sourced 3.64 diff. 10km after installation of 3.64 main bearings broke in a diff and locked both wheels in the middle of the motorway doing 80km/h. I got a 3.33 diff from E36 (with slight modification to adapt to e30). Used for a good few months until the head gasket went on my M10. recently M10 engine got replaced with M20B20, 5-speed box and 3.91 diff (which I know was in use with no issues before). I've driven about 20-30km and both wheels got locked again yesterday at around 80 km/h. The first time it happened there was a horrible noise coming from diff for a good few seconds before it locked the wheels, second time nothing at all just a big bang out of nowhere and both wheels got locked. Is it possible that something else is breaking diffs or I'm just very unlucky?
Thank you in advance for all of the advice.
2 broken diff's in 6 months
Moderator: martauto
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boiliebasher
- E30 Zone Regular
- Posts: 269
- Joined: Mon Nov 17, 2014 11:00 pm
Wow the car sounds a bit like Trigger's broom 
It sounds like you've been very unlucky. I've personally been driving RWD cars daily for over 20 years and never had the issues you've experienced (knocks wood!) Differentials are usually very tough and take A LOT of abuse before they start failing, especially the way you've described.
I bet you had no oil in those diffs. Like literally not a single of drop oil. That's the only way I could foresee a catastrophic failure like that under normal driving conditions, unless you're super unlucky. If you were constantly doing burn outs or drifting full chat every single corner you hit, thats a different story!
It sounds like you've been very unlucky. I've personally been driving RWD cars daily for over 20 years and never had the issues you've experienced (knocks wood!) Differentials are usually very tough and take A LOT of abuse before they start failing, especially the way you've described.
I bet you had no oil in those diffs. Like literally not a single of drop oil. That's the only way I could foresee a catastrophic failure like that under normal driving conditions, unless you're super unlucky. If you were constantly doing burn outs or drifting full chat every single corner you hit, thats a different story!
Last edited by boiliebasher on Tue Aug 22, 2023 1:34 pm, edited 1 time in total.
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boiliebasher
- E30 Zone Regular
- Posts: 269
- Joined: Mon Nov 17, 2014 11:00 pm
The only other thing I can think of is failing wheel bearings or brakes, but all that lot "should" of been picked up by an MOT.... Again for it to all lock up at 80kmph sounds odd to me and definitely not normal