How to spot an LSD?

[kntmikado]

This is an insanely noob question for me to ask, but I forgot and can't seem to find the info I read once upon a time.

How the hell do you visually tell the difference between a limited-slip and an open diff? I remember reading something about the LSD having heat fins all over it while the other didn't, but then that would mean my '91 NA has an LSD in it and I could have sworn no '91 NAs ever came with one, nor was the Sport Package available anymore. Did the White Package give an LSD for some reason? I can't imagine that it did, but you can never tell with car companies.

So yeah, what's the visual difference between an LSD and an open diff?

 

[Mr. Sinister]

Sticker that says LSD on it? :dunno:

 

[SupraMario]

Well besides visually, the LSD pumpkins had a metal tag stamped on it that said LSD and some other stuff. At least mine does.

 

[BorHor]

Do a burn out. 2 lines = LSD, 1 line = Open. I think LSD's were always an option for NA's. There is a way to read it off the chassis plate but I forgot which number it was.

 

[kntmikado]

So, it's starting to sound like both types of differentials have cooling fins on them.

 

[Piratetip]

Doesn't always work but:
Put it on stands, put in neutral.
Spin one tire, if the other spins the opposite way its open, spins the same way LSD.

Maybe you can look through the drain or fill holes to see the clutch packs?

 

[kntmikado]

Do a burn out. 2 lines = LSD, 1 line = Open. I think LSD's were always an option for NA's. There is a way to read it off the chassis plate but I forgot which number it was.

Um.. lol? My car, as it is right now, doesn't have enough power to do a burnout. Between my valve guides and cyls 5/6 not firing worth a damn (still haven't been able to diagnose it yet), I have all the power of a 1G-GE and the mileage of a muscle car. It drives fine, but no burnouts here.

If there's a sticker, I can't imagine it still being there 174k miles later. If I can't clean it up and see a tag or sticker there, I'll probably have to resort to raising the back end with jackstands and checking to see how the wheels turn. I'd rather use a lift, but I don't have one.

EDIT: Thanks, Piratetip. I needed that info.

 

[selfinfliction]

read the user manual the other day (yeah yeah i know)

the plate in the engine bay on the firewall will tell you.

if the 5th digit from the right side is a "3" or a "5" it has lsd. example:

xxxxxxxxxx5xxxx = lsd
xxxxxxxxxx3xxxx = lsd
xxxxxxxxxx7xxxx = no lsd

 

[BorHor]

^ thats what I was looking for.

 

[kntmikado]

read the user manual the other day (yeah yeah i know)

the plate in the engine bay on the firewall will tell you.

if the 5th digit from the right side is a "3" or a "5" it has lsd. example:

xxxxxxxxxx5xxxx = lsd
xxxxxxxxxx3xxxx = lsd
xxxxxxxxxx7xxxx = no lsd

It just so happens I have my VIN handy just about all the time (car folder FTW) and the number is a 5. So according to that, I have an LSD! Woo! Now to worry about the maintenance that probably hasn't been done on it and scour the forums. If there's some oil on the fins across the bottom of the LSD, how worried should I be? It's in the front quarter.

 

[SupraMario]

Um.. lol? My car, as it is right now, doesn't have enough power to do a burnout. Between my valve guides and cyls 5/6 not firing worth a damn (still haven't been able to diagnose it yet), I have all the power of a 1G-GE and the mileage of a muscle car. It drives fine, but no burnouts here.

If there's a sticker, I can't imagine it still being there 174k miles later. If I can't clean it up and see a tag or sticker there, I'll probably have to resort to raising the back end with jackstands and checking to see how the wheels turn. I'd rather use a lift, but I don't have one.

EDIT: Thanks, Piratetip. I needed that info.

Its not really a sticker, it should still be there its a metal plate thing that has been riveted onto the back of the pumpkin.

 

[ValgeKotkas]

It seems that yours is leaking. Mine leak(ed) too, oil gathered under it pretty fast. It needs new seals, and that's what I'm getting right now

 

[kntmikado]

Sounds lovely. Here's hoping it will last 'til spring, or until I can find a not-frozen place to do the work. Damn apartments without available garages.

 

[gelboy1015]

read the user manual the other day (yeah yeah i know)

the plate in the engine bay on the firewall will tell you.

if the 5th digit from the right side is a "3" or a "5" it has lsd. example:

xxxxxxxxxx5xxxx = lsd
xxxxxxxxxx3xxxx = lsd
xxxxxxxxxx7xxxx = no lsd

hmm, i have a 7, but my supra has a lsd diff.. maybe it was added by a previous owner?

 

[adampecush]

my "5th from the right" number is a 1. 89 turbo with LSD, so that theory is out. IIRC, the last 6 numbers of the vin tag are production numbers.

 

[BorHor]

Those are not for the VIN. They are for the chassis tag/plate in the engine bay.

 

[SupraMario]

Those are not for the VIN. They are for the chassis tag/plate in the engine bay.

Bwahahahaha, now I wonder how many people will post back: "shit never mind"

 

[BorHor]

Haha, Lets see..

 

[selfinfliction]

Those are not for the VIN. They are for the chassis tag/plate in the engine bay.

yeah... i figured "the plate in the engine bay on the firewall" would be specific enough.

internet > my judgement

 

[Poodles]

easiest way to tell a open diff vs LSD is jack up one rear tire (chock the fronts!!), release tha e-brake and put it in neutral.

Try and turn the wheel, it will rotate the driveshaft if it's open (or really REALLY worn LSD)

dunno about the torsen diffs though...