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Maual transmission fluid

Someone has to be jerking me around somewhere. Since I am getting the clutch replaced shortly I was going to get the fluid changed too. The dealer told me the weight of the fluid is “MTF 75W/85”. The local autoparts places all say that is axel lube, and really heavy for trany fluid. Tried googleing it and I cant find anything. Help, please.

Its an '04 Hyundai Tiburon GT, with a 6 speed manual. 60K salvage title.

I use redline MTF 75W90 in my MINI cooper so I would guess that the weight for your hyundai is correct.

Hyundai Motor Company of North America specifies API GL-4 SAE 75W-90 gear oil for the manual transmission in your vehicle.


Some manual transmissions use ATF…Some use 10-40 motor oil…And some, like yours, use gear oil, the same type that’s used in rear differentials. Commonly called “Ninety Weight”…

Ok, thanks.

But I sure as heck wouldn’t worry about changing it yet.

no, when the clutch is done. just want to make sure i show up with the right stuff

I don’t know how to pull the transmission without draining or losing gear lube. After 60K, I wouldn’t put dirty gear lube back in.

Get API GL-4 gear lube, 75W-90. That is the proper stuff for you.

I don’t think you will lose any transmission oil when it is removed from the engine.

Just out of curiosity, where did you acquire the vehicle? Recently?

If the tranny calls for GL-4 do NOT use GL-5. Some GL-5’s say they are compatible with GL-4…and they are NOT. GL-5 may contain sulfur which may eat away at at Brass gears. Just be sure to use the correct oil.

If you insist on changing the tranny fluid, go ahead, but I would not.