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gearbox oil

958 Views 14 Replies 8 Participants Last post by  IowaSmart451
Hello all,
I am doing my reluctor rings, and since I have the back end all apart, I figure I'll do the drive shaft seals while I'm at it. Obviously, pulling the driveshaft means replacing the gearbox oil.

What do you all use that I can buy US side for oil?
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Factory oil, you’ll need three bottles. Expensive.

The link to the discussion. Wow.
Royal Purple?
…my highly abused transmission gets Red Line MT90…

Jetfuel…pass on anything purple
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Here is one that is not approved of course, but is GL4 and a synthetic:

Ultra1Plus™ SAE 75W-90 Synthetic Gear Oil, API GL-4
Clint Wong, our smart car service manager recommend Royal Purple gear oil to me.
Haven’t had any issue using that brand. Over 100K miles on the clock. Any good
gear oil is good.
Valvoline SynPower 75w-90. You lose some inserting the bottle between the spring. The second bottle goes in easier if you squirt half of the bottle into the 1st one.
Valvoline SynPower 75w-90 Is not good, it is GL5
It sure did quiet the ride down and got rid of 55% of the "milkshaking" the Getrag transmission is notorious for.
It’s not friendly for the synchronized transmissions.
Here is a direct quote from Valvoline:

“Recommended for conventional and limited slip differentials and non-synchronized manual transmissions where API GL-5 or API GL-4 fluid is specificed”
Synthetic GL-4
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Mobil 1 Delvac 50
90 weight gear oil

Mobil 1 Delvac 50
90 weight gear oil

Why would you use a straight viscosity gear oil? SAE 50 is about the same as 90, but the 75w is equivalent to SAE 15 when cold.

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