TVPostSound

iTrader: (9)

All GL5 is compatible with LS.
They MUST HAVE friction modifier for the clutches.

I've rebuilt hundreds of rear ends in my previous career.

Do not wait till chatter occurs.

Black Betty

iTrader: (60)

Thanks. Will do.

easyrider

Maybe I am mistaken but my understanding is the G37 VLSD itself is completely sealed inside the pumpkin and the differential fluid used has nothing to do with it?

Please correct me if I am wrong.

Thanks for the great write up Black Betty - just what I was looking for.
Did you notice no capacity listed for differential fluid change in owners manual? Now i know to get two liters.

TVPostSound

iTrader: (9)

GL-5 rated gear lube, whatever make is your prerogative.

YeeP

Please, don't take this the wrong way, but why did you not pull the cover?
Is the cross member in the way? I have also built a lot of diffs, mostly for off road rigs, but I like to get a visual on the internals.

Black Betty

iTrader: (60)

I didn't pull the cover because it's absolutely not necessary for a routine fluid drain/refill. This was done as basic PM, not to correct any problems. Why would I want to? That would be just like dropping the oil pan for a routine oil change or pulling the heads to change spark plugs. Am I missing something?

You can if you like, but that's more work than is necessary for this job. The cover will get pulled when I eventually get around to swapping the rear rend gear out.

YeeP

I always pull the cover when doing a diff service.
You can clean out the diff and make sure the gears are getting a good wear pattern. No reason to get all defensive there man. I was just curious.

Maybe its because I like to build axles, so I want to make sure all is well in there. Being that this is a newer car, I would be surprised if it didn't have some kind of o-ring style seal in the cover. No scraping of RTV and the like.

Pulling the diff cover is hardly like pulling the head or the oil pan.....

Mike

iTrader: (1)

A bad wear pattern would be shown by lots of metal on the drain plug and/or chunks coming out.

Alternatively, an UOA could be done, which would indicate that as well.

YeeP

A really bad wear pattern (or bad driver, serious power, blah blah blah) might be indicated by metal chunks, but you would probably hear that driving down the road too.

A diff is always going to make metal, that is a fact. Look at the OPs pics, I'm sure he takes good care of his stuff, and it is probably wearing well.

Black Betty

iTrader: (60)

The thread's intent was simply a how to on how to perform the PM of changing the differential fluid, not anything detailed or with any expanded application other than basic maintenance. However, feel free to add to this write up with photos and the steps for pulling the differential cover and what to inspect for inside. You can expand it's scope since this a field of expertise for you.

It seemed to be wearing fine from what I can tell by looking at the fluid. But I'll know much more when it's time for the gear swap and a professional with a lot more expertise than me tears it open.

TVPostSound

iTrader: (9)

Metal in the fluid, is a bearing failing, not really bad wear pattern.

Bearing failure can be clearly heard.

A bad wear pattern will result in gear noise (high pitched howl) either during acceleration, float, or coasting.

Bad wear patterns in stock production cars are a result of worn carrier or pinion bearings.

There is absolutely no reason to pull the cover off, if there is a factory supplied drain plug.

The cover is sealed with RTV, if it aint broke, dont fix it.

Vu37

Has anyone tried using Royal Purple products for there rear diff and trans?

YeeP

Metal in the fluid can be caused by the "wear in" of the gears also. The bearings are a much harder metal than the gears, and I would highly doubt that the OP's carrier bearings/races have a wear problem that is shown by the metal on his plug (see pic on first post).

I don't care how good you are at setting up gears you are going to make metal on the break in. That is why on a fresh set of gears I do a 500-1000 diff service. I suppose at this point I would just call it a "more rigorous cleaning method". Personally, I want to see the gears, make sure all is well inside the diff.

Do you mean to tell me that a bad wear pattern in a production car can only be caused by a worn bearing? I have so much more to say on that, but I will end with this... Care to elaborate on why you feel that is the only way you can have a bad wear pattern on a production car?

SM_Shadowman

Question:
Red Line Synthetic Oil - Gear Oil for Differentials - 75W90 GL-5 Gear Oil

For that product, it says:
Contains additional friction modifiers for suitablity with clutch-type limited slip differentials - for most LSDs, no additional friction modifiers are required

So would that brand still need an addition friction modifier?

GTLAW

iTrader: (4)

I would say No!