Cman01

I may wish to change the fluid in the tranny and rear end. I have looked in the owner's manual and noticed the products that GM recommends that I use. Let's start with the trans.

GM calls for MTF part #88861800 in the states, #88861801 in Canada. Is this fluid synthetic???

I looked at Dreamin' post about changing tranny fluid and in the pics he posted the trans has a sticker on it saying to use Dextron 3 fluid only in the trans. So is the GM MTF really dextron 3?? If it is I could just use that ALA it is synthetic otherwise I'll use another brand of dextron 3 that's synthetic.

Now to the rear axle. GM calls for 75W90 synthetic axle lube part #89021677 in the states, #89021678 in Canada meeting GM specs 9986115.

I checked mobil and pennzoil synthetic rear axle lube with the proper viscosity but none of them advertise they meet the GM spec. So should I use the GM stuff or can I use the mobil/pennzoil stuff in this axle???? The additive will go in no matter what.

Tony

Cman01

any info on this guys????? Any opinions is appreciated. Thanks.

Xwet

I use RP in the rear. No chatter.
I used dextron 6, (this is the latest synthetic ATF), in the trans.
I have 7000 miles on my 07 Z06 and no issues. I do not track my vette.

Silver05GTO

I just changed the diff fluid this past weekend using Dreamin's post as well. Very easy job and my diff is quiet again. Make sure you buy the correct fluid, parts department pulled out GM 75w-90 synth for light trucks -it was the WRONG fluid. They special ordered the correct stuff for me. As in Dreamin's post the bottle looks the same and states the friction modifier is included already, took almost 3 quarts.

Bottle says Dexron LS gear oil *includes friction modifier. Stick with the GM fluid for the rear and do some circles/figure eights to work it into the clutch packs.

JoesC5

Factory fill for the transmission is Texaco ATF type III 1863. That is what is in the GM bottles you get at your dealer. I changed mine out with Mobil1 synthetic ATF Type III, but couldn't really see much difference. Also tried Royal Purple ATF and it made the shifting worse, so I replaced it with the Mobil ATF

Cman01

ok, I would like to confirm the fluid stuff before I go to get this done. Since the GM MTF isn't synthetic I will be getting Dextron 3 from whatever company (mobil or others) that is syn. and use that in the trans.

For the axle I will get the proper GM fluid since it is synthetic, now do I still add the additive or not? One person mentioned it has the additive in it already but GM still states to put it in. Would having too much additive be a bad thing????

AMGPilot

NOOOO!!!!

DO NOT USE DEXRON 3 IN YOUR MANUAL TRANSMISSION!

Dexron III fluid is no longer licensed and regulated by GM so any fluid labled DEXRON III may not be the same spec as the OLD DEXRON III.

That is why GM recommends Part Number: 88861800 Manual Transmission and Transfer Case Fluid.

Here is a link that shows pictures of the correct GM fluid to use: DIY - Transmission Fluid Change *Z06 Specific*

Here are some pictures of the front and back of the bottle:





Any fluid that meets GM Specification GM 9986252 would be a suitable substitute.

AMGPilot

GM came out with DEXRON VI fluid to replace DEXRON III for automatic transmissions and released their Manual Transmission and Transfer Case Fluid (Part Number: 88861800) for manual transmissions.

One would think that since DEXRON VI replaces DEXRON III that you could use it in your manual transmission but GM Document ID# 1897292 states not to use Dexron VI in manual transmissions or "FAILURE MAY RESULT".

Here is a copy of that document:



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It all has to do with the friction modifiers in the fluid. The friction modifiers in DEX VI is not designed for manual transmissions. That is why the owners manual tells you to use the Manual Transmission and Transfer Case Fluid (Part Number: 88861800).

Cman01

ok thanks for the info and the PM, so what proper trans fluid can I use that is synthetic since no one has confirmed whether the GM trans fluid is synthetic or not??

RichieRichZ06

You beat me to it Pilot.... I have been reading on here a lot that peopl are using Dex VI in manual trans applications and that is not OK per GM. The rear end fluid is 88862624 and the trans is 88861800.

RICH

AMGPilot

From reading the label I do not believe that the GM fluid is synthetic.

For synthetic fluids you have a choice of several manufacturers including Mobile One, Royal Purple, Amsoil and Red Line to just name a few.

The only thing you have to be concerned about is warranty issues. If you had a transmission failure and did not have the recommended fluid in your transmission then there is a chance that the warranty could be voided.

The new Manual Transmission and Transfer Case Fluid (Part Number: 88861800) states that it meets GM Specification 9986252. I could not find any more information on this specification number and I am not sure if any other brand of fluid actually meets this new specification yet.

I would recommend contacting the manufacturers of the other fluids and ask them directly if any of their products meet the GM Specification 9986252.

If you do, let us know what you find out

Cman01

I emailed Mobil about their fluids and whether it meets the GM specs as mentioned above for the trans and rear axle. Their reply was that none of their fluids meets the GM specs.

I guess I will use the proper GM stuff for the trans (even though it isn't synthetic) and the rear axle.

ipmtim

I used the Redline stuff in both the trans and diff. its synthetic made for racing. I don't race but if its good enough for the track its good enough for me.
I'm very happy with it.
Tim

corvet786c

So which Fluid can we use then just GM for now or what??
I would like to change mine out.

2k Cobra

Redline D4 in the trans. (Synthetic) I recommend

Latest greatest GM stuff in the rear. (No friction modifier type)

I grin every time I drive the car..

Let us know, 2k

GOLD72

Do not use DEX 6 in the manual transmissions.

Jumper11

OK I"m new to C5 ownership. I use 4 qtrs of GM 88861800 for my manual tranny. What is the transfer case? I know what it is in a 4WD vehicle. Is the transfer case seviced when you service the tranny? Or does it take additional fluid? The differential takes GM 75W90 synthetic axle lube part #89021677 in the states. How much to drain and fill the diff?

GOLD72

Corvettes don't have transfer cases. For a C6Z06 differential fluid change, you will need to buy 3 qts. Actual drain and fill capacity will be more like 2.5 qts so don't panic if it won't take the entire 3 qts. If you really have a C5Z06 as it appears from your post, you will need 2 qts as the housing capacity is the same as the other C5 vettes and there is no diff cooler. Same thing about the Tremec transmission. You will need to buy 4 qts but the actual drain and fill capacity is more like 3.6 qts.