Okay all, changing the MTF in my 2003 Mustang GT today, it is equipped with a Tremec TR-3650 5 Speed manual trans. Looking around online, I have found about 200 different ideas of what fluid is best to use in it, as both Ford and Tremec seem to have made different recommendations. I have narrowed it down (I think) to using either Pennzoil/GM Synchromesh, or Mobil 1 ATF, although I've also read that synthetic lubricants in this application are not good fot it. Anyone with experience with this transmission, please chime in! Thanks!
Last edited: