NW94Z

Looking to replace these fluids in the next month or two and I was wondering if I should just go with the GM over the counter fluids or are the aftermarket fluids better here like they are for engine oil? The DIY sticky for the Diff fluid change gives me the impression that the GM fluid is acceptable.

My only concern with the diff fluid is the GM LSD additive that comes premixed with the current GM sold fluid. Do I need to add the additive separately if I use a non GM brand like Redline?

TKOGTO

Contact Brad Neff (Subdriver here on the forum). He sells Amsoil products and is an excellent source of information about your issues and most everything else Corvette related. Good guy too.

Mookster

RichieRich recommended Amsoil for diff and tranny fluid, anyone try it?

This diff fluid
http://www.amsoil.com/shop/by-produc...e-gear-75w-90/
+
LSD additive
http://www.amsoil.com/shop/by-produc...-oil-additive/

and this tranny fluid
http://www.amsoil.com/shop/by-produc...mission-fluid/

Its noticeably more than GM fluids but if its worth i might as well get it? Anyone?

NW94Z

Looks like the Amsoil Diff fluid includes the friction modifier but it's recommended to add another 4oz to be sure. Apparently the Z06 diff requires a lot of the FM to eliminate chatter.

GOLD72

AMSOIL fluids in my cars for the past 5 or 6 years now.

capevettes

I did the rear diff and tranny fluid changes recently to my 06 Z06 and used the GM fluids recommended in the DIY. The GM rear diff fluid has the friction modifier in it. You do not add the posi lube to it. It quieted down my rear end which was making a little noise when cold backing out of the garage. I also used the GM tranny fluid which helped a bit with the cold notchiness when shifting but did not completely eliminate it.

C66 Racing

Thanks for the mention and sorry missed this thread this week.

Concur with the options listed above. The tranny and diff fluids are the same I use in my 02 Z06 at the track. However, the C6 diff clutch plates are made out of different material than the C5 diff clutch plates and need more additive. While the Severe Gear comes with friction modifier already in it, extra is usually needed for the C6 diff to prevent diff chatter.

More than happy to get AMSOIL products for forum members at dealer wholesale pricing, about 25% below retail, via the AMSOIL Preferred Customer Program. Drop me a PM if interested.

P.S. Note the forum name change and sorry for the confusion. Changed the name to more closely align with most of my posts these days which are related to my racing/business.

ZR-1 1991

Which fluid did you use ? My GM dealer tells me Dexron VI
But the owners manual says to use (p/n 88861800 for GM fluid)Manual Transmission Fluid .Which is correct ? I checked a 2013 owners manual is says to use Manual Transmission Fluid .

SergeantZ

I changed my engine oil/filter, trans, and diff fluid over to AMSOIL last year. For the diff I used the severe gear + GM additive, however my diff still chatters like crazy in parking lots. I'm about to change it out again with the newer GM formula that includes the additive to see if there's a change.

ss2z06

It is a different fluid for the manuals. Your dealer is wrong. They are probably similar but get the manual fluid.

K.Shupe

I've used these AMSOIL products in both my Z06 and ZR1 with excellent results.

AMSOIL Severe Gear 75W-90
http://www.amsoil.com/shop/by-produc...e-gear-75w-90/

AMSOIL Slip Lock Gear Oil Additive
http://www.amsoil.com/shop/by-produc...-oil-additive/

AMSOIL Torque-Drive
http://www.amsoil.com/shop/by-produc...mission-fluid/

Brad (C66 Racing) will take care of you, nice guy, GREAT service!

Just a note on my experience with the friction modifier additive. As has already been said the AMSOIL Severe Gear comes with friction modifier already added and too much can effect how well your limited slip will work. So the first time I used it (on the Z06) I only added 2oz, worked great, no issues. When I did the diff fluid change on my ZR1 I reduced the amount of additive to 1oz(easy enough to add more if necessary) and again no issues. Your milage may vary.......

Mark2009

Stay away from that dealer. He is going to break your car.

ToppThat

I used Royal Syncromax#01512 in the trans.4qts min. In the diff.i used 2-3 qts.R.P.Max Gear#01300 75W90 It said it had limited slip additive in it,i used a additive anyway and im very happy since i left stock hp behind long ago.Be sure to get your cooler line clips from dealer first(another rip off) And a lift is VERY helpful.Good Luck.

C66 Racing

Adding to those indicating your dealer is wrong...

You want 88861800 if you are going to use a GM fluid. The Dexron VI viscosity is about 25% lower than that of the original GM Dexron III spec which was the original GM spec for the Tremec manuals in GM applications.

GOLD72

Your dealer is a knothead for stating DEX 6 for a Tremec manual tranny.