changed out rear differential fluid

[jtulery]

PIP-5097

This is not for ZL1

[rtcat600man]

Originally Posted by ZO6 Bryan

Seriously, this procedure could not be easier. It's easier than the oil change.
Step 1: pull drain plug and top fill plug
Step 2: watch oil drain out
Step 3: replace drain plug
Step 4: fill it back up.
Step 5: replace fill plug

Not rocket science.

I have done mine twice now. At 2500 miles to get the factor break-in breaking in stuff out. Then again at 25K to see how it looked. Based on that, no issue going to 50K minimum. I used Royal Purple both times.

Tip of the day; remove the top plug first, just in case you can;t remove it after already draining the fluid out. You could be screwed at that point. Otherwise real easy to do.

Originally Posted by Schmo Z

How many quarts does it take?

Mine took 1 qt, but does not have posi. Those with posi take 1 qt. + a little of the anti slip stuff.

[Al C.]

If ur using GM oil, this is the Part# 88862624... No additional additive needed, you will need 3..

[AZ-ZL1]

The high performance shop I go to told me its beneficial to put in the 1st quart, add a bottle of the additive
(6 oz I recall) and top off with the 2nd quart. Additional additive for good measure particularly if you really drive her hard.

Sounded like good advice to me so thats what I did.

[Al C.]

If ur adding additive, your using the wrong oil.

[sycraft]

Originally Posted by Al C.

If ur adding additive, your using the wrong oil.

Not a correct statement... a lot of great oils need the additive.

[mmarx82]

Originally Posted by sycraft

Not a correct statement... a lot of great oils need the additive.

That was a correct statement, on the ZL1 the correct fluid already has the additive in it.

[ZO6 Bryan]

Originally Posted by mmarx82

That was a correct statement, on the ZL1 the correct fluid already has the additive in it.

If that is so, why do so many people have issues with the factory fill fluid in their ZL1's? You do realize they are filled with the 88862624 fluid from the beginning.

[Al C.]

Originally Posted by sycraft

Not a correct statement... a lot of great oils need the additive.

Sorry but It's absolutely correct ... I'm talking about GM recommended oil ZL1 specific not aftermarket stuff..

Originally Posted by ZO6 Bryan

If that is so, why do so many people have issues with the factory fill fluid in their ZL1's? You do realize they are filled with the 88862624 fluid from the beginning.

I don't think it's the fluid that is the issue rather than lashing compound but if you have proof otherwise please share.

[AZ-ZL1]

Originally Posted by Al C.

If ur adding additive, your using the wrong oil.

No, correct GM FLUID with additive...the 6 oz is simply additional slip differential fluid

[ZO6 Bryan]

Originally Posted by Al C.

Sorry but It's absolutely correct ... I'm talking about GM recommended oil ZL1 specific not aftermarket stuff..



I don't think it's the fluid that is the issue rather than lashing compound but if you have proof otherwise please share.

Where did this idea the sound is a result of lashing compound come from? It's just hearsay on this forum. No evidence anywhere that the noise comes from lashing compound.

[mmarx82]

Originally Posted by ZO6 Bryan

If that is so, why do so many people have issues with the factory fill fluid in their ZL1's? You do realize they are filled with the 88862624 fluid from the beginning.

I don't know why they have issues and don't pretend to know either but I have 6 bottles of it my storage unit ready for future services and they say the additive is in it already. I do realize that the 88862624 is what is filled in there from the factory. Also note that under PIP5097 that they drain and refill it three times with the driving requirements to scubb off the posi-parts with the 88862624 fluid. All I can think is maybe they didn't expect to have that much wear in the differential. Also this may very well be one of the many reasons they told everyone to take it easy for the first 1500 miles. IDK...

Based on that I don't think its wrong to use the fluid as is and I also don't think that using a separate additive in addition to it will hurt anything either.

[Stephen12ZL1]

buy 3qts...it takes a little more than 2 to fill the diff. I can say from experience that the original diff oil may be the correct part # fluid but it had a ton of milky white residue (lashing compound) and other contaminants in it on 2 ZL1s I have changed. On mine, I used royal purple for about 25 miles and the clutches chattered and moaned like crazy...no exaggeration. Swapped mine again to the correct GM fluid that has the additive included in it and all is well now. I have since swapped the fluid again because of the road course action and the fluid looked crystal clear in comparison to the initial swap.

[Al C.]

Originally Posted by ZO6 Bryan

Where did this idea the sound is a result of lashing compound come from? It's just hearsay on this forum. No evidence anywhere that the noise comes from lashing compound.

From MY personal experience, that's what it is.. Not hearsay..