I'm confused as to the purpose of what the OP is asking - I guess the question is more like "what is the reason people change diff fluid?" Rather than if it solely helps VLSD performance.

My testing shows on the highway at 80 mph in the winter for an hour or so my diff fluid reaches 194*. On the track in summer I'm sure it will exceed 300*. I'm hoping my diff cooler will keep the fluid under 250* and allow the VLSD to do its job.

That's the magnets job.

:iagree:

OP does have a point. considering the fluid inside the diff that makes the diff "lock" is sealed we dont have to change it often. i think the reason you should change it is after extended hard driving. oils break down and lose their effectiveness, and thats the reason i change mine out every so often

Thank you.
So basically the diff fluid we put in is just to help cool the vlsd. And as time goes by, the fluid loses it's viscosity and isn't cooling as efficiently, thereby causing the vlsd to overheat quicker and work as an open diff.

It's gear lube. Its in there to lube the gears. If it helps keep the vlsd alive longer that's a bonus.

To the ones who left sarcastic remarks, do you even understand how a VLSD works, or how it differs from other LSD's? My thread was to clarify part of the function and maintenance. I don't believe in blindly following a guide without thoroughly understanding why I should do it at all.

wat?

Thanks for clarifying

I was about to comment, then it occurred to me that I wasn't sure which parts were directly affected by changing the dif oil either...


Here's an exploded view of the 370Z dif

http://img27.imageshack.us/img27/5730/img1xwi.jpg

Which parts are sealed and non-serviceable vs not?

Outer gears are affected by fluid change, whereas inner locking mechanisms are not?

Is that correct?

Ok, looking at that diagram. Part# 38760 is inside the carrier. That would be the VLSD unit that is sealed with silicone fluid. Your gear lube would be seperate from that. The bearings inside the housing is pinion bearing part#38120, and part#38140. 2 carrier bearings, left side and right side, part#38440. Those are lubed with your gear lube.

To clarify - the VLSD uses seperate fluid, that is sealed within the LSD themselves. There is no servicing possible on this device. The diff fluid lubricates the gearing. The VLSD has it's own silicone fluid to act as the coupling.

^^^ Awesome -- thanks for clarifying, guys! Repped :tup:

:tup: