Can a LSD fail?

[float_6969]

Ok, so I have a 1990 240sx w/a LSD that I swaped from a HICAS car that had about 150,000 miles on it. Last night/today we just got our first snow of the winter. Obviously there is little traction on the roads. Now I've driven open differential before on this car and when I'm turning and such, the inside tire doesn't spin. But if I'm in a severe loss of traction (like in the snow) it feels like the axels aren't locking together like they should. It feels like they are both spinning, but the drive (passenger side) wheel is spinning considerably more than the drivers side wheel. Is there any way to test a LSD? I thought about tryin to powerbrake, but I wanted to check here first as I don't have a line lock to shut the rear brakes off.

[IvoryJ30t]

yes, if your talking about a viscous LSD, then they do wear out.

helical lsd's do not wear out, but they can only apply a ratio of power to the opposing tire. if one wheel has zero traction, it will spin.

a clutch type lsd will also wear out, but performs the best and lasts considerably longer than a viscous unit.

my j has 108k and the vlsd is kinda weak.

[float_6969]

It is a stock Nissan unit, an it is a VLSD. I know a clutch type can wear out. I don't know how a helical works. But unless I didn't understand how a viscous worked, I think think it could wear out. The way that I understood it, was there there was a silicone addative that was put into the gear oil. Attached to the output shafts of each axle was a plate with holes in it. Those plate are real close to eachother. When they wheels spin at different speeds, the silicone molecules heat up and expand, locking the wheels together. If this is how it works, then how can it wear out? I'm not second guessing you, I just want to understand.

[IvoryJ30t]

nope, the silicone fluid and plates are sealed in a seperate unit, not open to the gear oil. in a VLSD, you dont need lsd additive, because the unit is sealed

[corn322]

the silicone deteriorates after a while, and the locking abilities will be severly reduced, as you have noticed.

[nissanwalker]

Theunit requires some traction to work it depends on heat being generated by the torque to make it grip. If you have very little/no traction they will not work especially if it is an older unit and worn.

[float_6969]

well it's got probabally about 160K miles on it, and I don't exactly treat it real nice either. It really started to crap out on me when I started drifting in it regularly. Oh well, I guess I'll have to get a Kazz now, hehehe...

[Q45tech]

My guess that on something powerful and heavy like Q or 300zxtt that by 100-120k they are not working as new! Obviously snow vs the South has a lot to do with life.Finding low mileage wrecked cars for substitution is the only economical method.

I could really tell the difference when I changed my 220k unit for a 50k unit in a 90Q.............which now has 88k on it.

Very few pay the $2600 for a new diff.

[IvoryJ30t]

i wanna go KAAZ also. i wonder if there are any differences between the kaaz and nismo clutch lsd's? they are about the same price.

[IvoryJ30t]

the kaaz and nismo clutch lsd units are in the 850-900 price range. then you have to install it. big PITA.

[float_6969]

I heard that Kazz actually makes NISMO's unit for them, but that was just hearsay. As far as the install goes, there won't be any cost for me as I have/have access to all of the required equipment.

[IvoryJ30t]

oh, im a mechanic. installation cost doesnt mean a thing to me. its just a pain to do it. as long as the gears are meshing properly, and there not worn, you dont really have to worry about the pinion shim, and the ring gear mesh.

if the gears need to be replaced it sucks because you have to put it together and take it apart multiple times untill its shimmed correctly and the pinion meshes the ring right.

[float_6969]

Oh, I know. I've done them before. It sucks...