What are the required fluids for the C6 (2011) manual trans and diff? I used the search but did not find the specific viscosities or requirements. Are friction modifiers required for the diff?

Thanks.

 

The diff does require modifiers, some oil blends include them others need to be added.

I run Redline in the diff and Amsoil in the tranny.

 

I agree and use the same !

 

They should all use D4 ATF or equivalent.

We have always ran RedLine D4 ATF in our street and race cars with zero issues.

 

D4ATFAmsoil Severe Gear for rear end.

 

The GM diff fluid has been changed, the current version is called something like "GM Dexron LS 75-90 Gear Oil". If you find a 2009 or later Owner Manual online, it will tell you the correct stuff.

It already has the friction modifier in the fluid, no need to add any and some say it's actually harmful to add it now.

Our 2009 came with that diff fluid, I had it changed at around 7k miles and again at 50k miles, sent the 50k sample to the lab for analysis. They said both the fluid and the diff were in excellent condition, you can look up the thread I started if you wish.

 

I'm in the process of changing them right now after break-in (3K miles). Am sticking with GM's Dexron LS for the diff, since it's fully synthetic, and has exactly the right amount of FM in it. But I'm switching to Amsoil Torque-Drive Dexron-III tranny fluid. For the engine, stayed with Mobil1 5w30. Am going back to fill tranny and diff now, start engine, put tranny in 2nd gear and let it idle for a minute, and top off. I'll also recheck the tranny, and top off if needed. Hope Amsoil gets rid of the damn cold 'crunching'.

 

Only GM for me.

 

Definitely DO NOT use the newest DEXRON which is DEXRON VI (6) in the manual trans. I have Mobil One Synthetic ATF Dexron III in mine.

 

I have ATD in my 07 and it is about as "notchy" as the standard Dexron was when cold. When it's warmed up, it shifts very well.

I thought the 08 and up 6MN was smooth as butter...

Every manual I have ever owned was notchy when cold. ... Back in the day, (60's), you needed a crowbar to shift when it was cold.

 

That is for sure...even aftermarket fluids for D6. Oddly enough there is not enough friction with that fluid for the syncro's to operate correctly.

 

Just changed my transmission M6 fluid ,with Mobile 1 ATF . Seem much smoother to shift . I had the temp sensor drain plug . Managed to just squeeze it up hill by drilling a plastic oil cap ( mobile 1 ) and getting a tight fitting clear 7/16 " hose . 4 good 10 second pushes , the quart was empty . It only took about 3.5 quarts . I have about 42 K on the 05 .

 

TSB: #07-04-20-002A
Date: 01-09-2008
Document ID# 2048181

2005 - 2008 Chevrolet Corvette

Subject: Rear Axle Clunk and/or Chatter Type Noise on Turns
(Drain/Refill Rear Differential Fluid) #07-04-20-002A - (01/09/2008)

Models: 2004-2008 Cadillac XLR (Including V-Series and Export)

2005-2008 Chevrolet Corvette (Including Z06 and Export)

This bulletin is being revised to change the fluid recommendation and to remove the requirement of adding friction modifier. Please discard Corporate Bulletin Number 07-04-20-002 (Section 04 -- Driveline/Axle).

Condition:
Some customers may comment on a clunk and/or chatter type noise from the rear of the vehicle while making turns.

Cause:
This condition may be caused by slip/stick of the posi-traction clutch plates due to insufficient limited-slip axle additive. As plates slip and stick, a jumping or jerking feel occurs accompanied by a clunk noise.

Correction:
Important: DO NOT remove the differential cover from the rear or the two sides. It is not necessary to flush the old fluid from the differential.

Drain and refill the rear differential fluid using the procedure listed below.

Draining Procedure:
Raise and support the vehicle. Clean any dirt from around the differential drain plug. If not equipped with a differential cooler, remove the drain plug (1) and washer (2) from the differential.

If equipped with a differential cooler: 4.1. Using a bent tip screwdriver, remove the quick connect fitting retaining ring (3) from the quick connect fitting (4) and discard the retaining ring.

4.2. Remove the differential cooler inlet pipe from the differential nut.

Drain the fluid.

Filling Procedure:
If not equipped with a differential cooler, install the drain plug (1) and washer (2) to the differential. Tighten the differential drain plug to 35 N•m (26 lb ft).

If equipped with a differential cooler: 2.1. Install a new retaining ring.

2.2. Connect the differential cooler pump inlet pipe (2) to the differential. A distinct snap should be heard or felt when assembling the cooler pipe to the fitting.

2.3. To ensure the cooler line is properly installed, give the cooler pipe a gentle pull.

Clean any dirt from around the differential fill plug. Remove the fill plug and washer from the differential.

Important: DO NOT add any limited-slip additive (friction modifier). With this new fluid (Dexron LS Gear Oil 75W-90) it is no longer required to add friction modifier. If friction modifier is added, it will cause the fluid to lose some of it's friction reducing properties as well as reducing seal life.

Fill the differential with the new DEXRON® LS gear oil, P/N 88862624 (Canadian P/N 88862625). Refer to the table listed below for lubrication specifications.

Check the fluid level to ensure it is even with the bottom of the fill plug hole to no lower than 6 mm (0.25 in) below the opening. Install the fill plug and washer to the differential. Tighten the differential fill plug to 35 N•m (26 lb ft).

Important: Steps 8-13 are for vehicles equipped with the differential cooling system. For vehicles not equipped with the cooling system, proceed to step 14.

Raise the vehicle so the wheels are about a foot off the floor. Make sure the wheels can spin freely without obstruction from the hoist or any nearby items. Start the vehicle and put the transmission in second gear. Slowly accelerate to 10 mph and hold this speed for one minute. Turn the vehicle off. Raise the vehicle. Check the fluid level in the differential. Add fluid until the recommended level is reached. Lower the vehicle.

Once the differential fluid has been changed, the vehicle must be driven in 8-10 tight figure eight maneuvers to heat the fluid and allow the fluid to be worked into the clutch plates.

Lubrication Specifications Application

2004-2005 XLR (Including Export) and 2005 Corvette (Non Export)
1.72 liters
1.85 quarts

2006-2008 XLR (Including V-Series and Export) and 2006-2008 Corvette (Non Z06)(Non Export)
2.0 liters
2.11 quarts

2005 Corvette Export
1.88 liters
1.99 quarts

2006-2008 Corvette Export (Non Z06)
2.16 liters
2.28 quarts

2006-2008 Corvette Z06
2.75 liters
2.91 quarts

Parts Information:
Description: DEXRON® LS Gear Oil
Part Numbers:
88862624 (US-1 Quart)
88862625 (Canada-1 Liter)

Warranty Information
For vehicles repaired under warranty, use:

Labor Operation: F9709*
Description: Drain & Refill Rear Axle Fluid
Labor Time: 0.6 hr

* This is a unique labor operation number for bulletin use only. It will not be published in the Labor Time Guide.

© Copyright General Motors Corporation. All Rights Reserved.

 

These are AMSOIL's recommendations:
AMSOIL Torque-Drive Synthetic Transmission Fluid (Product Code ATD1G)
AMSOIL Severe Gear Extreme Pressure Synthetic 75w90 (Product Code SVGQT)
AMSOIL Slip-Lock Differential Additive (Product Code ADATB)

I use the tranny and diff fluid in my 02 Z06 at the track. But, while the Severe Gear comes with friction modifier already in it and the C5/C5 Z06 does not need more additive to prevent diff chatter, GM changed the characteristics of the C6 diff and most C6 diff need more additive to prevent diff chatter, thus I'd recommend at least a few ounces of the Slip Lock Additive.

 

Any updates from people using different fluid?

I have redline synthetic in my diff 75w - 90? I cannot remember.

 

Ok just to clarify. The best trans fluid to use is dex III? Synthetic or non? Also the rear is 75-90 but does it need an additive or not? Thanks.

 

I would use a synthetic Dex III in the transmission. The diff does require a LS additive; some come with it (GM) and some don't. You will have to read the label or ask.

 

Thanks. I plan on getting the K&W additive.

 

To clarify, Dex III was both a GM specification and a GM branded name fluid. Both were superseded. GM's new part number for manual transmission fluid is 88861800.

There are aftermarket fluids, both synthetic and non-synthetic that are labeled to meet the old Dexron III spec including the AMSOIL Torque Drive ATF I linked above. Personally, given how hot the tranny in the Vette gets when driven hard, I wouldn't use anything but a synthetic in it.

The GM diff fluid for the C6, Dexron LS, has lots of additive in it to help combat the chronic diff chatter of the C6 diff. Aftermarket fluids such as the AMSOIL Severe Gear 75w90 I linked above usually have friction modifier in them. The amount of friction modifier in fluids like the AMSOIL Severe Gear 75w90 has historically been enough to prevent diff chatter in previous gen Vettes but not the C6. Most C6 owners who use the AMSOIL Severe Gear 75w90 add at least a few ounces of the AMSOIL Slip Lock additive I linked above. I would suspect, but don't know, that it would be similar for other aftermarket diff fluids.

Note that diff chatter won't harm the diff, just bothersome. An approach is to use a fluid with additive, see if the diff chatters. If not, all good. If it does, open the diff fill plug and squirt in a few ounces of additive and see if it still chatters.

 

Have Redline D4 on the shelf ready to go in/