[ISO1le]

Originally Posted by Alpha1BC

DEFINITELY change the fluid ASAP and then again very soon after the track event. It's cheap and easy insurance and keeps the warranty intact. The point of changing the diff fluid is to flush out the clutch disk filings from break-in that can damage the ring/pinion and accelerate clutch disk wear. If you get rear end groan or wear out the disks before the warranty is up, you'll probably have to fight with a dealer to replace it under warranty if there's no documentation supporting that the fluid was changed properly during break-in, and even then there's still a chance of being denied.

I also am under the impression that the reason that you're supposed to change again after your first track day is because you get stronger clutch engagements and higher wearing on the track that will create more filings than you would with just street driving.

After the two initial break-in fluid changes, you're also supposed to change the fluid after 24 hrs of track driving IIRC (check your manual to confirm the correct number of hours).

To answer your initial question, ACD 10-4034 is the OE fluid that GM uses from the factory. Everyone is gonna have opinions and suggest different fluids based on preferences, but really you should be just fine so long as the fluid you pick has the required certifications and specifications. I've been using that ACD fluid in mine without issue, but I'm sure there are other fluids that work if you want to use something different.

Aside from that, seems like you've got a good handle on initial track prep. After that it's just a matter of keeping up with the fluid (engine oil, trans, diff, brakes) and consumable (tires, brake pads) changes and you'll be golden!

Thanks for your response. I guess if that's the case i'll go with the OEM fluid. How long do you have after the track event to change the diff fluid?