E30 Zone

How do I know if I have a limited slip diff on my e30?

The VIN states that it does have but can I check to see if someone has changed it for an inferior normal diff? When I acquired the car the diff bolts holding it to the chassis were loose so I want to make sure it's not been swapped. I've just had the diff flanges replaced also and need to make sure the right oil has been put in. TIA for any help

there should be a tag on the back plate.you need to remove this and wire brush/sand paper it up and it should start with an S, you could spin it up on a right turn or left and see how many black lines you've smoked

the best way is to lift the rear of the car up on axle stands.

If both wheels turn in the same direction when spun, then it is a limited slip diff, if they spin in the opposite direction, then its not. this however doesn't tell you what condition the clutch plates are in though.

I believe that if you only jack up one side and then try and turn the other wheel, with a torque wrench on one of the wheel nuts it will take approx 80 ft/lbs (or is it Nm, I can't remember) to make the diff slip, assuming the plates are good, less if they are worn. But I would let somone else more knowledgeable quote what torque it should start slipping at.

Hope that helps

light the tyres up feck this approx 80 ft/lbs (or is it Nm, I can't remember) malarkey.

i know which idea i prefer.

magpie wrote:light the tyres up feck this approx 80 ft/lbs (or is it Nm, I can't remember) malarkey.

i know which idea i prefer.

Mr Pikey,
as stated above, that is the correct way to test a LSD , with a torque wrench, not the suggestion one has made.

ooh pass the torque wrench squire ,


pikey indeed






that's what a trippy diffs meant for

magpie wrote:

that's what a trippy diffs meant for

LOL

Wow - there's a lot of knowledge out there. Thanks people. I have to admit to being a lightweight mechanic and don't usually mess with torque wrenches. Oil changes and polishing my beloved e30 yes.

there should be a tag on the back plate.

I notice the back of the diff looks like a toast rack. Are you talking about wire brushing this and looking for the tag with an 'S'?

If your diff looks like it has spent the best years of its life on the deck of the titanic, then you are best off jacking it up and seeing what direction the wheels rotate, rather than showering yourself in powdered rust to try and find/clean the tag whilst laid up under the car on your drive.

Neil_uk7 wrote:Wow - there's a lot of knowledge out there. Thanks people. I have to admit to being a lightweight mechanic and don't usually mess with torque wrenches. Oil changes and polishing my beloved e30 yes.

there should be a tag on the back plate.

I notice the back of the diff looks like a toast rack. Are you talking about wire brushing this and looking for the tag with an 'S'?

no,look to the top left of the back plate and there you should find a
tag like this,



but full of rust!

Goody! Will take a look tomorrow. I'm never keen on jacking my car up lest I put the trolley jack through the hull....

the hull

just drop the clutch at 5k.. if it's an is make sure it's rattling the limiter.. you might find out.

Bob_S wrote:just drop the clutch at 5k.. if it's an is make sure it's rattling the limiter.. you might find out.

or it could go BANG!

nope. It's a cabby (have I just lost my street cred)?

you never had any!

magpie wrote:

Bob_S wrote:just drop the clutch at 5k.. if it's an is make sure it's rattling the limiter.. you might find out.

or it could go BANG!

A Bm go bang? you're having a laugh. Only one I shafted was an m50b25 with a lame lambda sensor which I didn't bother changing.

Neil_uk7 wrote:nope. It's a cabby (have I just lost my street cred)?

Depends on what size engine you have in the cab.
B20 won't have a LSD, and the ratio will be about 4.2 smallcase.

B25 might have a LSD, and will have a range of diffs.

a slush box will

What's a slush box? Mine's a 325i cabby from 1988 with chrome bumpers (I can hear you cringe now)! According to BMW it has an LSD. But they also said it had cloth interior and headlamp wash wipe from the factory but someone has fitted leather and ripped the headlamp wash wipe out (probably flogged it on fleabay).

ah a chromie b25.
you are in the running for a trippy diff.
slush box = auto btw

slushbox = automatic

Its easier to take the tag off to rub down and read, held on by one bolt

You can test by getting one wheel on grass and the other on the road then try and do a wheelspin, if you fly forward you have LSD if you dont you have open wrongness


I prefer the dump clutch test myself

what's a trippy diff? (I'm beginning to feel silly)

maybe only the wipers and motors are missing from the h/l/w/w kit.are there any black wiper st0ps on the head light rings or do you have an 'S' on the wiper stalk?

now were talking

leeparkes wrote:Its easier to take the tag off to rub down and read, held on by one bolt

You can test by getting one wheel on grass and the other on the road then try and do a wheelspin, if you fly forward you have LSD if you dont you have open wrongness


I prefer the dump clutch test myself

Show off

There are no black wiper stops on the headlights but there is some waterworks plumbing behind them. Never looked for an 'S' on the wiper stalk. Still, one less thing for the chav's to rip off.

Neil_uk7 wrote:what's a trippy diff? (I'm beginning to feel silly)

erm LSD. sometimes i worry.

Rav335uk wrote:

Neil_uk7 wrote:nope. It's a cabby (have I just lost my street cred)?

Depends on what size engine you have in the cab.
B20 won't have a LSD, and the ratio will be about 4.2 smallcase.

B25 might have a LSD, and will have a range of diffs.

Why wont a 320i cabrio have one?

LSD's were an option on all E30's, even 316's!

Neil_uk7 wrote:There are no black wiper stops on the headlights but there is some waterworks plumbing behind them. Never looked for an 'S' on the wiper stalk. Still, one less thing for the chav's to rip off.

if you press the wiper stalk in towards the ignition or pull back on it to wash the screen every 5th or so time it will dump washer fluid out behind the head lights.

do you have a double or single washer bottle?

Single washer bottle only. Don't think I've ever tried pressing the wiper stalk inwards. I only found out recently that the indicator stalk has a push feature which is labelled BC - turns out it cycles through the OBC. Who would've thought it

obc remote 80's style.

sounds like you never had the lamp washers,or some one took a good deal

find somewhere featuring tarmac and a low friction surface - attempt a speedy getaway. If you snake off leaving rubber on the grippy side, then you have a lsd

..like I found out today

mmmm elevenses