How to tell if it has a LSD?

[dudecati]

Hi - I'm picking up a new to me '91 318is. I've heard that some came with an LSD and some didn't. How would I check if mine has one or not (PO doesn't know). Also, is there any maintenance that should be done to the diff?

Thanks!

[navytapaul]

Raise the rear and spin the back wheels. Lsd will spin the same direction, open will go in opposite directions

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[mulletman]

Go find some wet leaves on the road during your test drive. The previous owner will be overjoyed with this behavior.

[ButtJuice]

Get under the rear and find the tag on the diff, it will say the ratio (most likely 4.10) and if it has an 'S' it's an LSD

[jntar]

Crawl under and look for a metal tag on the rear of the differential. It should say some numbers. The letter "S" will be in front of the numbers if it is a limited slip.

[James]

Do a massive skid on the test drive. Or check the tag.

[kway]

Crawl under the car and look for an S on the tag.

Or jack it up and spin a wheel; if the other one spins in the same direction it's LSD, if the opposite direction it's not.

See, I have all the answers!

[graveshaker]

By now many of these S tags are long gone. Do what the first post say if tag is gone.

[long tall eta]

if it's an is and hasen't been swapped out it will be an lsd. also a 6k clutch dump will tell.

[jlevie]

By now the only sure way to tell may be the tag (or an S painted on the differential). The clutches in an LSD could be worn to the point that it will behave like an open differential.

[evandael]

take it out of the car, take off the cover, and if you can see spider gears inside the diff unit, it's open. if you see a solid clutchpack unit with windows to see the clutches, then it's a limited slip.

[CrusherCurtis]

Search!!!!!!!!!!!!!!!!!!!!!!!

jk

[dudecati]

Thanks all, appreciate you helping the noob out!

[getouth]

if it's an is and hasen't been swapped out it will be an lsd. also a 6k clutch dump will tell.

only the second part of this answer is true.:)

[88SuperETABD]

rev to 4k rpms and let go of the clutch, then floor it! then after you ring it out, slam it to second, then get out and check your tire marks, if theres two its an LSD, 1, Open.