Any issues with using synthetic mtx transmission fluid on a car with dino motor oil? This may seem like a really dumb question. Don't want to debate merits of dino versus synthetic motor oil, just want to know if there are any issues.

My car has been having really rough shifts lately so I plan on putting in either the redline MT-90 amsoil gl4 75w90.

 

The fluids you are discussing are for manual trannies -- so assume you have that kind of tranny. The motor oil goes in the engine and the tranny fluid goes in the tranny. Two separate places and they never mix. So there are no issues with synthetic in the tranny and dino in the engine.

You don't say how many miles you have on your Max. I put synthetic fluid in my manual tranny at about 36 K miles and wish that I had done so at about 20 K or so. I then changed the synthetic fluid again at about 95 K miles. I really like the synthetic and could really feel the difference when I first replaced the original fluid with synthetic. You need to be certain that this fluid is a GL4 and not a GL5 fluid. I am using the Amsoil and talkinghorse on this site can get you a really good price on the Amsoil fluid.

Good luck.

 

I figured that it wouldn't matter at all because of that, but I just wanted to be sure. I am paranoid about that sort of thing.

Miles are 74k, original. Car has had dino motor oil since purchased by the original owners (my parents), and I plan on swapping motors for a 3.5 in a few months, so its going to keep with the motor oil, and whatever I swap will run synthetic. I will be running synthetic transmission fluid now that I know there are no issues.

 

Swapped it in, and it made a huge difference. Car shifts great!