b16a27

ok is there any type of lsd tranny that u cant see through where the axles go if there is (witch i think there isnt) what kind is, is it called viscous LSD

Audi RS4

The viscous coupling is often found in all-wheel-drive vehicles. It is commonly used to link the back wheels to the front wheels so that when one set of wheels starts to slip, torque will be transferred to the other set.
The viscous coupling has two sets of plates inside a sealed housing that is filled with a thick fluid, as shown in below. One set of plates is connected to each output shaft. Under normal conditions, both sets of plates and the viscous fluid spin at the same speed. When one set of wheels tries to spin faster, perhaps because it is slipping, the set of plates corresponding to those wheels spins faster than the other. The viscous fluid, stuck between the plates, tries to catch up with the faster disks, dragging the slower disks along. This transfers more torque to the slower moving wheels -- the wheels that are not slipping.

When a car is turning, the difference in speed between the wheels is not as large as when one wheel is slipping. The faster the plates are spinning relative to each other, the more torque the viscous coupling transfers. The coupling does not interfere with turns because the amount of torque transferred during a turn is so small. However, this also highlights a disadvantage of the viscous coupling: No torque transfer will occur until a wheel actually starts slipping.

A simple experiment with an egg will help explain the behavior of the viscous coupling. If you set an egg on the kitchen table, the shell and the yolk are both stationary. If you suddenly spin the egg, the shell will be moving at a faster speed than the yolk for a second, but the yolk will quickly catch up. To prove that the yolk is spinning, once you have the egg spinning quickly stop it and then let go -- the egg will start to spin again (unless it is hard boiled). In this experiment, we used the friction between the shell and the yolk to apply force to the yolk, speeding it up. When we stopped the shell, that friction -- between the still-moving yolk and the shell -- applied force to the shell, causing it to speed up. In a viscous coupling, the force is applied between the fluid and the sets of plates in the same way as between the yolk and the shell.

95lstegman

mm yes and no mister. in AWD cars with a center VLSD, the viscous fluid is different than perhaps a RWD car with a rear VLSD. the AWD car's VLSD fluid needs to provide viscosity at a greater difference in speeds while the RWD VLSD's fluid will be engineered to provide more lockup for a certain amount of difference in velocities of the plates. lots of things may vary, such as plate design and material and size and the fluid is infinitely variable in makeup.

back to the topic though, it's not likely you'll find a viscous differential in a FWD tranny. they need special fluid and like to be surrounded by heavy fluid in general, opposite of Honda trannies at least.

d16dcoe45

The original b13--Sentra Se-R came standard with a viscous LSD. They are probably all WORN out by now!! They didn't last usually more than 50-70,000 miles.

95lstegman

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by d16dcoe45 &raquo;</TD></TR><TR><TD CLASS="quote">The original b13--Sentra Se-R came standard with a viscous LSD. They are probably all WORN out by now!! They didn't last usually more than 50-70,000 miles.</TD></TR></TABLE>
well, you proved me wrong. i know that the rear VLSD in such equipped 240SX's and other Nissans don't really go bad. at least, i've never seen one go really bad. i haven't driven a bunch of them, so i can't attest to how well they maintain their response depending on age, but i think in general age is not a factor when buying a used one. BTW, they're sealed units (R200V if you care).