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LSD Confusion

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Old 11-19-06, 07:08 PM
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LSD Confusion

So i was under my car today cutting and replacing some rusty exhaust tubing. i was looking at my diff and i noticed yellow numbers in paint, looks just like the junkyard marks on my alternator, so im thinking mabey this is an lsd. i didnt have time to look as it was getting dark and i needed to finish welding. so i took it our for a spin and everytime i did a burn out it left 2 solid black stripes. what do you guys think? Does anyone have a pic of a stock '87 diff? thanks a lot.
Old 11-19-06, 07:25 PM
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with the car in neutral and the ebrake off, jack the back of the car up and spin one wheel. see which way the other wheels spins.
Old 11-19-06, 07:29 PM
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well i cant right now. but shouldnt the both spin the same way.
Old 11-19-06, 08:33 PM
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S4 Limited Slip Diff. Typically LSD's will have a tag on the FILL (upper) plug that says LIMITED SLIP ADDITIVE REQUIRED, or something to that effect.

My S4 Open Diff looks exactly the same.

To tell what type of diff it is, turn one wheel and watch the other.

Open diff = wheels turn opposite direction (one forward, one back)
Clutch diff = wheels turn same direction (both towards front or back)
Viscous diff = other wheel doesn't turn or takes a sec to move in the same direction.
Old 11-19-06, 08:55 PM
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well i left my jack at a friends but i got under the car. it looks ecactly like that but i couldnt move well enough to see what the fill plug said.
Old 11-19-06, 09:01 PM
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Originally Posted by Cpt.Zanzibar
So i was under my car today cutting and replacing some rusty exhaust tubing. i was looking at my diff and i noticed yellow numbers in paint, looks just like the junkyard marks on my alternator, so im thinking mabey this is an lsd. i didnt have time to look as it was getting dark and i needed to finish welding. so i took it our for a spin and everytime i did a burn out it left 2 solid black stripes. what do you guys think? Does anyone have a pic of a stock '87 diff? thanks a lot.
what model do you have.

And two burn out strips mean you hve a traction problem... it has nothing to do with a LSD
Old 11-19-06, 10:45 PM
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i have a base model.
Old 11-19-06, 10:54 PM
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well then it didn't come with a LSD. You would need to jack up the rear and, turn one wheel and see if the other moves the same direction or the opposite direction to see if someone swapped in a LSD

And as a note, if you have the base sized wheels and tires, and you couldn't break both tires loose, I would be surprised.
Old 11-19-06, 10:56 PM
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Originally Posted by drewl
with the car in neutral and the ebrake off, jack the back of the car up and spin one wheel. see which way the other wheels spins.
You spin one wheel forward and the opposite wheel should turn in reverse.
Old 11-19-06, 10:58 PM
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Originally Posted by dwb87
You spin one wheel forward and the opposite wheel should turn in reverse.
if you have an open diff, yes.

However if you have a working LSD, they both will spin the same direction
Old 11-19-06, 11:13 PM
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Originally Posted by Icemark
well then it didn't come with a LSD. You would need to jack up the rear and, turn one wheel and see if the other moves the same direction or the opposite direction to see if someone swapped in a LSD

And as a note, if you have the base sized wheels and tires, and you couldn't break both tires loose, I would be surprised.
i knew the base didnt come with an lsd which is why i never looked into it.

well the last burn out i did left about a 15 foot double stripe. i can get the tires to totally break loose. fairly new tires too.
Old 12-10-06, 10:40 PM
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Originally Posted by Twofer


S4 Limited Slip Diff. Typically LSD's will have a tag on the FILL (upper) plug that says LIMITED SLIP ADDITIVE REQUIRED, or something to that effect.

My S4 Open Diff looks exactly the same.
To tell what type of diff it is, turn one wheel and watch the other.

Open diff = wheels turn opposite direction (one forward, one back)
Clutch diff = wheels turn same direction (both towards front or back)
Viscous diff = other wheel doesn't turn or takes a sec to move in the same direction.


so viscous diff still go the opposite way if the diff (pumpkin) is out of the car?
Old 12-11-06, 12:02 AM
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that the difference between and open diff, clutch diff, and a viscous diff. well the other day i jack my car up and found a tag that says lsd. its a S4 Gxl
Old 12-11-06, 12:13 AM
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Originally Posted by rx7-kid
that the difference between and open diff, clutch diff, and a viscous diff. well the other day i jack my car up and found a tag that says lsd. its a S4 Gxl
Yes, a 86-88 GXL should have a factory LSD
Old 12-11-06, 12:26 AM
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Originally Posted by vspc2nr
To tell what type of diff it is, turn one wheel and watch the other.

Open diff = wheels turn opposite direction (one forward, one back)
Clutch diff = wheels turn same direction (both towards front or back)
Viscous diff = other wheel doesn't turn or takes a sec to move in the same direction.


so viscous diff still go the opposite way if the diff (pumpkin) is out of the car?

ok, now im confused. i have an S4 sport. and the sticky FAQ says no sport from 87 had an LSD. but when i jack the car up, one wheel turns, and the other just sits there. if i spin it for a while, then the other one will start to move. and it dosent seem to matter which side its on....so? do i have an LSD?
Old 12-11-06, 12:40 AM
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Originally Posted by blmcquig
ok, now im confused. i have an S4 sport. and the sticky FAQ says no sport from 87 had an LSD. but when i jack the car up, one wheel turns, and the other just sits there. if i spin it for a while, then the other one will start to move. and it dosent seem to matter which side its on....so? do i have an LSD?
Not from the factory.

And for it to have a viscous diff that someone installed after the fact, then it would take a spin or two and then spin the same direction.

Anytime a wheel spins the opposite direction, it is an open diff
Old 12-11-06, 12:42 AM
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put in gear, i did the same thing and was so happy till a friend said "NOPE.....TO BAD"

awwwwww no lsd lol
Old 12-11-06, 12:43 AM
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icemark i pm'd you
Old 12-11-06, 01:07 AM
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Originally Posted by vspc2nr
put in gear, i did the same thing and was so happy till a friend said "NOPE.....TO BAD"

awwwwww no lsd lol
does it matter if its in gear or not?

EDIT

Originally Posted by drewl
with the car in neutral and the ebrake off, jack the back of the car up and spin one wheel. see which way the other wheels spins.
nevermind.
Old 12-11-06, 01:25 AM
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i tink so...........
Old 12-12-06, 02:13 AM
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ok....so i read that a miata LSD will work in my S4. Does anybody know and i swear i saw it some where here, but does anyone know the link??
Old 12-12-06, 02:22 AM
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no, i cant remember where the link is, but if you type "miata LSD" in the search, you will get a bunch of anwsers, and its like the 3rd or 4th one down. its the torsen diff from the 94-97 miata 1.8 liter. and it fits all 2nd gen. NA diff boxes, but something about equal link driveshafts or something...i dont remember...im tired, ive been looking for one also for the last several days. nothing yet, but if you find a source, let me know, the cheapest ive found so far is 750 plus 50 shipping.
Old 12-12-06, 02:55 AM
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what the f***! if i spin one rear wheel of my S5 TII the other one doesn't move, even after several revoultions of the first one! what't up with my diff? i think S5 have LSD? what's wrong with mine??
Old 12-12-06, 03:09 AM
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Originally Posted by airworks-fc3s
what the f***! if i spin one rear wheel of my S5 TII the other one doesn't move, even after several revoultions of the first one! what't up with my diff? i think S5 have LSD? what's wrong with mine??

your diff might need to be rebuilt. only S5 GTUs(note the "S") and Turbo models have VLSD.
Old 12-12-06, 03:46 AM
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so my diff might be worn out?? 'cause i had some serious traction problems at the 1/4-mile this summer! i had one choice: launch like a grandma', everything else was wheels spinnin' like crazy...


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