What fluids to use?

[rwood126]

Ok...I'm doing a Transmission , t/c , and diff service this weekend. It's a T-4 with a 300 t/c and stock diffs. What is the best fluid for the Transmission ?

I've heard ATF...Sychromesh...gear lube. What do you use?

 

[TrebleHook]

Brother....all I can say is "search" -- you'll get so many opinions/answers that you'll be more confused than when you started....

That said, take a look at what comes out of the tranny when you drain it. I'll presume the tranny is working well (even if it iS a T-4 ... --- and if so, you should try to simply replace what is in in it.

It's easy to to tell the difference between Gear Lube (thick and smells like sulfur/yack spit), ATF (red), and Synchromesh (thin like motor oil).

My guess is that you'll find gear lube. (I run GL-4 rated StaLube from NAPA.)

Do your research -- but trust your Transmission . If it's working well, don't mess with it.

Cheers,
TrebleHook

 

[rwood126]

^^

You are so right. I've heard it all. I ran Mercon v in my Mustang T-5 . The T-4 is not much different. The problem is ...I'm not sure when the PO changed the fluids. I've only had it for 2 weeks...and I don't want to wait much longer to change it out. It is my DD ...so I want the best for it.

 

[CJim7]

80w90 in the 300...
Do not use gear lube in the T-4 . The T-4 and T-5 originally used Dexron III...ATF. Gear lube will eat the synchros.

 

[TrebleHook]

And so it begins.....

 

[CJim7]

And so it begins.....

Yep. I was having this debate 20 years ago when I ran a T-5 in my CJ. Gear oil is a no-no.

 

[Old Dog]

I wouldn't trust what comes out. My cj had ATF in the Dana 300 when I got it. WRONG

 

[jamie]

so how much fluid goes into the Dana 300 ?

 

[Sasquach]

so how much fluid goes into the Dana 300 ?

Till it spills out the fill hole-or is it a level hole?