Gear oil in T5?

[SabinStangs]

I installed a new clutch on my 89 LX yesterday. As soon as I pulled the driveshaft, I was greeted with that all too familar stench of gear oil. I thought that all T5's required ATF? Seeing most of the work performed by the previous owner, I wouldn't be suprised if he screwed that up too. I got everything buttoned back up, but I'm waiting to find out what type of fluid I should put in it? I drained all the gear oil out of it, but do I need to flush it out if I switch to ATF? Thanks in advance...

 

[67coupe]

It should be ATF. I use Mobile 1 Synthetic. That choice is up to you.

Might be worth it to fill it with ATF, get the tranny up to temp, and drain/refill with fresh ATF.

 

[Manewaymja2]

I wouldnt think that you would have to flush the Tranny but i use Castrol ATF in my car (Mercron 3 / 4 i would think should be ok). I know you dont use gear oil.

 

[57fairlane]

gear oil? does it have synchros?

 

[67coupe]

True story.

Helped a buddy replace a clutch on a 93 GT in college (10 years ago, no knowledge of 5.0's). Had everything bolted up but the shifter. Went to the local autozone to pick up some tranny fluid. Asked the guy at the counter what we needed. Dude gave us 3 quarts of gear dope.

Good thing we didn't fill it. He called a knowledgeable friend of his to double check, about flipped out when he heard what autozone gave us.

Went back to get a refund and pick the proper fluid. The DA that gave us the gear dope repeated told us ATF was wrong and that we were going to ruin the tranny.

 

[SabinStangs]

Nice! I couldn't believe it was in there in the first place! Could be what has been causing some shifting issues lately. I can't wait to drive it with the right fluid, new King Cobra, fly wheel, and Tri-ax! I hope my new rear main doesn't leak...

 

[faststang90]

i got a tko years ago and it had a paper in it and it said atf

 

[NIKwoaC]

Gear oil will RUIN a T5. I've found that conventional ATF shifts the best in a T5, synthetic seems to be too slippery for the syncros to work their best. I actually use B&M Trick Shift in mine, since its nothing but a high end conventional ATF, and its easy to find/cheapish.

 

[Brando5641]

the syncros have pretty much the same matterial that the auto clutch plates.
Gear oil will not let the syncros grab the gear to make it match the speed of the slider and you will grind gears untill you start loosing gears and it wont shift...


I think you should put some cheepo tranny fluid in and drive it for about 10 min and flush and refill with whatever you want. ATF is a realy good cleaner so i think it will clean most of the oil out.