bmwe21.net forums

Hi,
I have a 316 1.8 automatic. (m10b18 i think).

I have had a noisy diff for quite awhile and I've decided it's high time i addressed the problem.
I have previously taken it to my mechanic who's first attempt was to put some additive in it, but this has not worked.

Can someone please tell me what I need to do to get this fixed as I have no clue (and I have the feeling my mechanic is not interested in fixing my car anymore.)

1) Does a replacement diff come as one part? if so,
2) which do I need? (i'm confused as I've searched the forum and I see there different ratios and lsd's etc which is way over my head)
3) where can I get one from?
4) How much of a job is it to fit the diff?
5) Perhap's it can be repaired/reconditioned?

any help is much appreciated. this is my daily runner and now even the radio is struggling to block out the noise.

Just stick another diff in it mate. You can get one for about £40 to 50 and it's a relatively simple job. An hours labour should cover it. Don't waste your time with additives.

Did you check our own specs page? http://www.bmwe21.net/?page_id=282 shows you that you prolly need a 4.10 final drive diff.

Anyway, I agree with Mark, get a decent used example and you'll be fine at a decent rate.

ok - thanks guys. I'm going to take your advice and post a wanted post in the forum but before I do so...
couple more questions...
on the specs page the 316 is stated as ratio 3.91 but i think this relates to a 4-speed manual. is it the same for the 3-speed auto? (when i go to gearbox types it says "more detailed specs coming soon"

is there a opportunity to upgrade here? what effect does putting a higher ratio diff (e.g 4.1) have?

How about lsd? would mine be lsd, and if not, is it better to look for an lsd?

You're right your car has a 3.91 regardless if it's an auto or manual, lol I should visit my own pages more often

I'd stick to that spec, a 4.10 is shorter meaning your gears will be shorter and you'll rev more on the motorway. A longer version like a 3.64 will reduce motorway revs but it will take a long time to pull away from the traffic lights haha

LSD's offer improved traction but I don't expect any gains on a 316 auto tbh, might even work against you if you take your foot off the accelerator in less grippy situations like rain or snow because of the auto box torque converter. I'm pretty sure you car doesn't have a lsd atm for the same reasons.

Hi,
Is the 3.91 diff used on my 316, used on any of the e30's (might help in my search for one)

Nope

im finding it really hard to find a diff for my 316 auto (3.91 ratio)
i read on the wanted forum that someone with a 316 was looking for a 4.10 ratio diff.
would a 4.1 work ok for mine? i ask becos i hear these are on the e30 318is.
alternatively, does anyone know anywhere who might have one? ive tried the wanted forum.

I'd just go with whatever is available and see how you get on with it. 4.1 seem quite hard to find.