I want to change my T-5 Trans fluid but don't know the Viscosity to put in. I know it holds 6.6 pints/3.1 liters.

I want to put in Amsoil.

Which one do I use:

Manual Synchromesh Transmission Fluid 5W-30

-OR-

Manual Transmission & Transaxle Gear Lube 75W-90
??

 

Use ATF

 

Check the T5 sticky for more confusion, but I'd use synthetic.

 

I agree with Apeiron. Especially if it is a world class t-5.

 

Yup, your year should use ATF.

Not the gear lube.

Synchromesh might work but I'm not sure, I'd go with what I know, if I was still tearing up T-5s every few weeks.

Synth wouldn't hurt I'm sure.

 

I have a manual T-5 Transmission. Why would I use ATF?? Its not an automatic.

The Amsoil website does say to use ATF for my 1989 T-5.
Too me that doesn't make sense.
It says to use MTF for a 1987 T-5, they used the same transmissions for both years, so to me its a little confusing!!!

My T-5 Trans is the M39.

I ordered the 5w/30 Synchromesh trans fluid. That should be ok, right?

I would hate to put in regular ATF in a manual trans.. to me that doesn't make any sense!

 

Because Borg Warner designed it to use ATF.

 

The 87 was the 1st design T-5; used brass blocker rings, same as old 4-speeds and such.

In 88 GM started buying the 2nd design T-5 for these cars. It uses blocker rings with an organic lining, specifically, the same material that auto trans clutches are made out of.

That's why yours uses ATF, but the 87 uses gear lube.

 

Here's the link I allude to above. You'll see that while GM does cause some confusion, they do recommend ATF.

https://www.thirdgen.org/forums/tran...ything-we.html

JamesC

 

And my 85 shop manual says ATF. Ah, GM what a bunch of funny guys!

JamesC

 

Yeah; on the 1st design T-5, GM waffled back and forth between ATF and gear lube more than once, I guess depending on who won the coin toss that year, the warranty dept or the CAFE compliance dept. On those, like any older design manual trans, basically any petroleum-based lube at all is OK, even motor oil.

I always used to use ½ ATF and ½ STP in my old 4-speeds... made a Muncie shift so slick you could almost just throw the shifter into the next gear and it would go, and even made a T-10 bearable. I used that once in a T-5, right after I got the car with one in it (traded in a T-10 car on it), and couldn't even tell it was going into gear at all, it was just there. A little too slick I guess.

 

Yup, SAE40 makes a pretty decent substitute for 75W90 in a pinch. Might shift a little notchy when cold on some transmissions. There are lots and lots of applications out there that specify motor oil for the transmission, and even a few with a shared sump that used the same oil for the engine and transmission.

 

Cool... Thank you so much. I love this site. All you guys rock!

I'm cancelling my MTF and ordering Torque Drive ATF!