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Driving on LSD...

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"¦.or not?
Had the rear of my car on stands and spun the wheels in 1st. One wheel spun, the other did slower then stopped. Do I have LSD or is it just broken? In neutral wheels spun same direction together.
My code on the sticker is AOS which is non LSD. AOT would mean you have the LSD option.
Apparently there is also a code stamped on the flange on top of the transaxle, but is hard to get to.
Car 89 S2
I have already used the search function to no avail.
 
With both wheels in the air if you spin one with LSD the other goes in the same direction and without it goes the other way (or not at all if there is enough brake drag) IIRC. [FONT=verdana,geneva"] [FONT=verdana,geneva"]If yours go in the same direction then the definitive test is to keep one from turning and try to turn the other - if it goes then no LSD, if it doesn't then you have one.[FONT=verdana,geneva"]
 
Beaky, unusually, has an LSD box without cooling coils. I would expect all later LSD boxes to have cooling coils, or did they only fit them on Turbos? Other than looking for coils, which should confirm an LSD if present, go with Fen's option.

Another method is to dump the clutch at 5000rpm. If both wheels spin you have LSD, if only one spins you haven't, or someone has put the wrong oil in and lashed it up, or it's broken.
 
I think the optional LSD pre-Silver Rose had no cooling, Silver Rose standard LSD ad the cooler as did all others fitted thereafter.
 
Hang on a second. If you are engaged in 1st gear with the rear axel in the air surely with an LSD you wouldn't be able to turn the wheels at all? With a normal diff the opposite wheel would turn in the opposite direction irrespective if you are in gear or not.
 
Good point, with the rear wheels in the air and an LSD and the car in gear the engine would have to turn to allow either wheel to rotate.
 
I think you will be able to turn them but they will be stiff. The LSD is not fully locking but has some slip.
Tony

(But I could be thinking of one wheel on the ground in neutral)
 
ORIGINAL: 944Turbo
The LSD is not fully locking but has some slip.
Click to expand...

perhaps a limited amount of slip? [;)]

locked in gear, the wheel will turn, but the amount of slip will determine if you can do it by hand. generally not......

As has been said, jack it up, put it in gear (but not with engine running) and turn the wheel. the wheel should turn the same way for LSD, or the opposite for a normal geared diff.
 
Slip means the speed of one wheel relative to the other. With an LSD this slip is limited so you will never get the situation that one wheel is stationary whilst the other is spinning like mad absorbing 100% of the engine torque/power, it will always send a minimum % of power/torque to the stationary wheel, therefore both wheels are driven at all times, therefore as Fen said, in order for the both wheels to be rotating the engine must turn if the car is in gear. This is certainly true for a mechanical LSD which uses a frictional clutch plate system.

However i'm not 100% sure if the same is true for a viscous coupled system that uses the viscous drag of a fluid to ensure that both wheels are powered. It could be that at the very low speeds you could manually turn a wheel there is not fast enough viscous drag generated to jam the rotation of the axel against the compression of the in-gear engine, as the viscous drag of the fluid increases with the greater speed differential of the driven shaft compared with the individual wheel.

 
The 944 LSD is mechanical, and what we are sayng is that if one turns then so must the other and if the car is in gear also the engine.
 
I'm all confused?
I think I don't have LSD.
Maybe I am just driving powered by one wheel, in circles.
I will be raising the car again soon as I could not get my rear spacer nuts undone as I wanted to adjust the handbrake. Also still trying to track down my noise which has come back with a vengance.

1 I can't remember properly now but I think car in nuetral I could turn one wheel and the other turned also. I thought they were going same direction but not sure now.

2 Gear engaged. As above.

3 Gear engaged engine on both wheels turned, one slowed down and stopped. I spun it by hand and it picked up again. Then slowed and stopped.
 
1 sounds about right. there should be less resistance on the prop than in the diff.

2. as long as they turned the same way, it sounds like an LSD to me

3. sounds like the brake dragging. maybe too much...? could it be fooling the LSD to thinking the wheel is always in contact and turning in that direction?
 
But my option code is for non LSD. I think in my service history there would be a fairly substantial bill if it had been retro fitted.
I think I will follow Johns advice, it must be floored in the interest of science.
 
ORIGINAL: pikey7
2. as long as they turned the same way, it sounds like an LSD to me
Click to expand...

Duuh. me dumbass! of course they shouldn't turn the same way. I'm gonna put my head back into GT4 now. [:eek:]
 
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