So should I use ATF or something else in my GT?

[drag0nfan's04GT]

Well, I planned on changing the fluids this weekend in the manual tranny, as well as, the differential. I went up to the store and since the Royal Purple products are all behind the counter, the clerk bagged them up and I was on my way. I got home and realized that he'd given me ATF. I took it back and both guys at NAPA said that I should just use the same gear oil as the rear. Actually, they gave me the 75/90 instead of the 75/140. I came back to work, and after some light Stangnet reading, I'm now thinking that I should go back again and get the ATF again.

Has anyone heard of this, or is it just me? What weight is the ATF anyway? I'm just asking since I've read a 100 threads saying to put in ATF into the manual, but one or two that say uses a manual fluid. I would normally go with the majority on this one, but I had to ask if anyone has used 75/90 or any other rear end oil in the front. It''s all Royal Purple if that matters.

 

[joekd]

Napa is wrong, ATF (Mercon spec) is the correct fluid to use for your tranny

 

[drag0nfan's04GT]

Well, that's what I was thinking. After reading up on this for the last couple of hours. I have found that most everyone says to use ATF in these transmissions. I was planning on going with Royal Purple, since that's the oil I use and no one around here has any of the other top brands. Does anyone know the difference between the ATF and the Synchromax fluid that they sell?

 

[40th GT]

ATF is the fluid recommended by Ford and Tremec. However, people get away with Synchromax and other manual trans fluids without problems.

I would go with what the manual recommends, just to help myself sleep better at night.

 

[the98stang]

Use mobil 1 synthetic ATF. It's Mercon approved.