stromadd

Which gear oil should I go with? I have the 3.42 differential assembly and just not sure...

70-75W90 Red Line 75W90 Synthetic Gear Oil, Quart $7.95 Buy Wish


70-SPG-H Red Line ShockProof Synthetic Gear Oil (Heavy), Quart $8.95 Buy Wish


70-SPG-L Red Line ShockProof Synthetic Gear Oil (Lightweight), Quart $8.95 Buy Wish


70-SPG-SL Red Line ShockProof Synthetic Gear Oil (Superlight), Quart

MHVette

I have been running Redline 75W90 since January and have had no problems... I believe I purchased some of the Redline Friction Modifier as well but I have heard that the 75W90 from Redline already has it in it! I'm sure someone will correct me if I am wrong!

stromadd

What's the difference between their regular and the shockproof?

Richin Chicago

Shockproof oil has a lower coeficent of friction and is great for racing as you will have less losses. But I don't think it is good for limited slip applications and I know it will void a warranty.

Redline 75W90 Gear Oil is a very good product I have been using for years. It has 4% friction modifier built in which seems to be just right for the C5.

LoneStarFRC

I agree with Richin Chicago

David426

75w90 is great stuff

C5Jim

I've used RedLine for years. One of the first things I did was to put Redline MTL in the MN6 and 75W90 in the rear end.
It's great stuff.

LoneStarFRC

How come the MTL and not the D4 ATF?

C5Jim

It just shifts better with the MTL.
I tried the D4 and saw no difference in shift quality. I called Redline and they said I could use the MTL, but may have stiff shifting in exteme cold. I had it out this winter with the temp at 6 degrees and it was a little stiff, but no much and not for long.
The main reason for MTL is because it does a great job of protecting the tranny.
I just had a rebuild done on a BW T5 with 320,000 on it (300,000 on MTL) The rebuider could not believe how good all the gears, syncros and bearings looked, considering the mileage.
BTW , he too sugested D4, but said stick with what works.

Monks

Redline makes a 75W90 and a 75W90NS, the NS contains
no friction modifier and the 75W90 contains 4-5%. (I think
GM spec is 5%) On my autocross car I mix to get 2%.
No problems with "chatter"

Russ

c3andc5

I'm a fan of Mobile 1 Synthetic for both engine oil and gear lube.

Cruncher

FKING1

Me too, only D4ATF in the tranny.
Fred

LoneStarFRC

Good info. Thanks.

C66 Racing

AMSOIL reformulated their gear lube line last fall. I use their best gear lube in my car which sees pretty extreme use and I've never had a failure. In fact, earlier this season, I lost a diff axle seal early in the race, but ran until the finish (26 laps). At the end of the race my diff was a quart low but still working fine (I won).

AMSOIL Severe Gear Extreme Pressure Synthetic 75w90

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Greenhead

DTE sends out two quarts of Red Line 75W90 Synthetic Gear Oil with their differentials. I trust what they put in their differentials. I use it too.