Well I have an 88 GTU, and it is suposed to have an LSD from the factory, just a few minutes ago I jacked up the back of the car and turned one wheel and the other would spin with it, but when you whipped the tire the opposite was the other wheel would keep going the same way. Also when I put the car in gear with the rear end still in the air, and turned one wheel with the car in gear the other wheel would spin the opposite way. So do I just not have an LSD or is the clutch in my LSD just worn out. Also is there any sticker or tag or a certain number or letter on the vin number that tells me that it has an LSD.

 

yes, they can wear out..

 

yes, just like the clutch in your tranny, they eventually wear out.

 

easy LSD check:
find some nice dry pavement, a light color is preferred.

Get in car. Insert in first gear. Rev to ~7000 RPM. Release foot from clutch pedal rapidly. Observe the markings left on the pavement. If there are two, your LSD is fine. If there is only 1, you should have some concerns.

 

that is not always true, i have a 90 gtu... no LSD, and i leave 2 marks, thats not always accurate

keegun

 

do one tire on low grip ground (grass/water/etc), and one on pavement.

 

and look for what kind of markings???

 

see if both tires spin.. If just the easier tire spins, you have an open diff or a worn out clutch. If they both spin, your limited slip is working properly.

 

Or jack up the rear of the car and spin the tires by hand. If they go the same direction, it's working. If the other tire spins the other direction it's messed up.

 

Some one on another thread had mentioned a tag on the differential were exatly would this be I look but didn't see one, is there acually supposed to be one there.

 

Also for cbrock,

 

On my GXL there is a metal tag on the drain plug on the Diff. On others I have not seen it, its just a little tab and can be broken or taken off easily..

 

Well if it is broken off easily I probably broke it off with a jack a while back, but at any rate it isn't there anymore.

 

Most on road vehicles don't have a very high preload so if the amount of traction is very different only one wheel will spin. Even with the very HIGH preload of off road vehicles, my trucks diff I can still get only one wheel to spin at times (the other wheel is in the air- it happens). Limited slip diffs are not positrac or lockers. Also after the friction plates in the diff have had lots of wear the preload is very very low. Still better than nothing though.

 

Ahhh, OK when I put one wheel off in the grass it did leave a very faint mark on the pavment, but it probably still needs rebuilt.

 

The lifting the wheels and turning trick doesn't work. The 88s use a limited slip additive that senses different wheel speed, solidifies and makes the plates grab. I would definitely start with a drain and refill with the limited slip fluid (1 whole tube) then top to the correct level with synthetic or regular gear lube.

 

That is incorrect, the 89-91 LSDs are fluid type. The 86-88 LSDs are clutch type.

 

What does that tab say? Mines covered in dirt and cant read it. I tried cleaning it and the sticker started coming off

 

So has anyone actually rebuilt one of the s4 diffs? Difficulty level? Where did you get the parts? Ive been cruising mazdatrix's site and have come up empty handed. They have new lsd's for like 1500 bucks... Ill pass in that case.

 

Brand new Mazda ones for $250 (for the LSD/diff only) to $500 for the whole gear assembly with LSD/diff are at Mazda Surplus:
http://www.mazdasurplus.com/Mazda.htm

 

SR Motorsports (www.srmotorsports.com) has MazdaSpeed LSDs for $799. Still a bit pricey, but much better than the torsens from mazdatrix.

 

Mazda Surplus also has a minimum order of $2000...

 

yeah, they only charge you $50, if you are under than min order amount.

 

Wow that mazdasurplus site is awsome, I have never seen that web site before. Thanks for that Icemark.

 

Yea, Mark is right: S4 uses clutch-type that wears out but is usually pretty reliable. the S5 has a Viscous LSD that uses snot that thickens up when it gets agitated. It only thickens up to join the 2 driven axles if one starts going faster than the other. I can understand if you can spin 1 wheel w/o the other turning on an Viscous. If you have a clutch type and they dont stay locked together, then your clutch pack is probably worn out.

Id just get a new Clutch diff and swap it in. Screw the viscous, i like mine to be lightneing quick. the Viscous is slower to react in a low-traction situation, like Drifting

A torsen is even better, but its purly mechanical. its also the same type as FD and Miata SE's use, they swap right into our diffs... but one guy was saying he tried a torsen on a road track. he blew his diff when he hit the the apex of the turn and his inside tire lost traction and came back down.