a noob diff question...

[emmi]

sorry for a reposted question but... what are the different types of diffs out there?? exactly.. which one do i have?? i have a 85 325e... and i know its not an open end, i can do doughnuts going clock wise and couter clockwise... anyways... can someone please help...

[92 mtechnic cabrio]

Just because you can do donuts doesn't mean you don't have an open diff.

I have a few friends with open diffs that can do donuts just fine.

On the E30, there are two different stock types of LSDs
LSD - Limited Slip Differential, at a certain load, the rear wheels lock up to prevent all the excess power going to one wheel and peg legging your car. (318is, 325is, M3, late-model 325i with LSD option, 325es?)
Open - Open diff, the rear wheels do not lock up. (earlier 325i, 325e, 318i, 325?)

What type of LSD the E30s have, I'm not too sure..

By the way, the numbers like X.XX just denote what the final gearing is for that differential. Common E30 diffs are 3.73 and 4.10. 3.73 in 5-speeds and 4.10 in automatics is the usual explanation.

[PeaveyBassist]

325e's come with 2.93's. My 1987 325e had LSD. There is a tag on the right side of the back of the differential. It has a bunch of numbers on it. If it starts, "S293"...its a 2.93 with LSD. If there is no S, its just an open 2.93.

Will

[emmi]

aight, it was lifet at the muffler shop earlier today, and i took that chance and cleared the dirt..... there was clearly an S in the beginning

[Garageaholic]

then you probably have the LSD of 2.93.

[emmi]

kool thanks for clerifying for me... i noticed it kinda leaks sum fluid on the back (the cover thing) what can i use to seal it up? is there a seal for it, or do i have to apply sum sealant???

[Magic_Black]

I have a 1989 325is (Manual).

What is the original LSD Ratio for that specific model.

I tried to read the tag, but it already has rotted away.

I also have an 88' 325is(auto) for parts, does anyone know what the stock differential is in that?

[Garageaholic]

magic black, you have a LSD 3.73 in all probability
you have the sport model which came with an S3.73.

I think that your auto '88 325iS has a LSD 4.10 (gearing different to make up for automatic driveline loss)


EMMI You need to buy diff output/input shaft seals, Hell while you're at it, just get a whole seal kit and do it at once...

haha, DON'T apply sealant. just replace the gaskets/seals

[Magic_Black]

Would the 4.10 diff be better in my 89 325is(manual), is there any significant advantages to have a higher diff. in ur car?

[Garageaholic]

That's your cue to do a search.....
but to answer ur question. you'd get better acceleration, but lower top speed.
some would think that 1st gear would even become useless

[ehlpitel]

To check if you have a limited slip jack up the rear of the car, if both wheels spin when you spin one, you have limited slip IIRC.