I was just doing some reading and came across an article which made me think: It said that after around 60,000miles, a VSLD starts to act just like an open differential. I didn't explain why, I'd imagine the oil inside breaks down and losses the properties which enable it to function properly. Anyone have any experience or thoughts on this?

I called my local dealership - my guy there said he's had a few people come in over the years to replace some bearings on the diff, but has never heard of the whole unit being replaced. It's one of those things where if it wasn't working, you wouldn't really notice unless you tested for it.

I'm not overly concerned, either way.. I'm just one of those people that, if my car has something, I'd like it to be working.

 

The VLSD oil is the same as the transmission's oil. Just make sure to replace it either with drain and refill or flush every 30k or so.

 

I was under the impression that the differential was sealed from the factory and fluid replacement was not possible.

 

I had VLSD on my old AE and I could have sworn I remember reading in the esm that it took part in the transmission's fluid.

 

I'm not sure you're totally off with that... my understanding though, is that the differential's core has some sort of silicone solution in it which makes it work, and that fluid IS sealed inside. There could very well be an outer shell which uses tranny fluid.

 

From:
http://en.wikipedia.org/wiki/Limited_slip_differential

 

Unfortunately the FSM doesn't cover specifics on the AE internals (either that or I haven't found it yet).

The owner's manual doesn't mention the VLSD needing attention at any certain point either.

 

well I imagine it wouldn't since it's core has to be replaced if it wears out..nothing that can be maintained by regular maintenance.

I think the dealer said it would be around $300 for the part, but who knows how much they'd charge for labour.

 

Bump...

We have finally had some cold weather and ice up here so I decided to give my LSD a little test (2k3 w/70,000 miles). It was raining and there where patches of wet ice in front of my house, about as low traction a situation as you can get. With both front tires on wet ice they both spun (I pulled the parking brake and let the car idle in first gear). With 1 tire on wet ice (parking brake on) it would spin a bit then the other tire would start to spin and try to pull the car forward.

Not the most scientific test but it would seem my LSD is working at least partially at 70k miles. LSD was an option I spent some time looking for, I hope it continues to work at least to some extent while I own the car.

 

unfortunately we're having a warm winter up here so until it snows and ices I can't do any of my own tests.. that's a good idea though, I will try it.

 

The 02-03 has a torque sensing LSD the 01 AE has a Viscous (fluid based) LSD

 

different mechanism, but they achieve the same result though, do they not?

I'm not completely sure of the mechanisms used in the 02-03 max, but my understanding is that you don't have to worry about it busting out on you at 60k miles like the VLSD.

 

I believe you can also take a beefy torque wrench to the axle nut with one tire grounded and one up and see if it's working.

 

the viscous coupling on the diff is a sealed unit and has its own internal fluid. but the entire differential assembly sits in the tranny case, half-dunked in tranny fluid.

and yes, the VLSD units can and do wear out- lifespan depends largely on the driving conditions they're put in. I can tell you though that my VLSD is still working at 230,000 miles and I've put it through Hell. It probably doesn't hold as much torque as it used to, but it still technically works.

As for a test, jack the front end up and put the car in neutral. spin one wheel. if the other wheel spins the same direction, the VLSD is working. If the other wheel spins the other direction, then it's dead.
you can also stick one wheel on the ground while in neutral and measure the torque required to turn the other wheel. breakaway torque should be above about 40 ft-lb before it starts turning.

unfortunately, there are no real specs in the FSM on it other than that. since it's a sealed unit, there's no way to service the viscous unit. if it's dead, you just replace the whole diff assembly (for about $800).

 

Find some gravel or fresh snow

 

you can test to see if your diff is still working. jack the car up, with the car in neutral spin one wheel, if it spins the same direction then the diff is working correctly, if they spin the opposite direction then the diff is not functioning correctly. You have to be in neutral, if your in a drive gear they will spin opposite direction either way. thats how to check as per the FSM. I know my car before my original tranny blew with 180K miles it still worked. I know occasionally one wheel will spin but right after the other will spin too. Same thing if i put my foot down while going around a corner, the inner wheel will spin then ill feel a tug on the wheel and the car pulls through.

damn Matt93SE beat me too it. :P