Tremec 3650 fluid 02 Mustang

[daemontrym]

When I bought the mustang it had 127k on it and shifted good, but notchy. So I drained the old fluid which looks like it was original. Then added in Mobil 1 Synthetic ATF which is Mercon V compatible on the back. The car shifts alot better, but feels like it could be smoother. What would you guys recommend? I have seen everything from Pennzoil Synchromesh, non syn Mercon V, Mobil 1 Syn ATF with 1 qt of Lucas Transfix, Redline D4, and AMS Syn ATF.

The clutch works fine and the cable is not binding.

 

[aquariuscsm]

I've driven alot of standard tranny Mustangs,and I think it's just the nature of the beast. They'll never shift silky smooth like a front wheel drive Honda (probably because those cars have cable driven transmission links). Mustangs are more of a direct linkage setup. Mine's a direct linkage setup too,the shifter is directly attached to the tranny,but has rubber bushings all over the place that smooth the shifts out and take away all the vibrations. I have a solid shifter mount that I had installed awhile back and solid brass bushings that replaced all the rubber ones. That removes all of the rubber from the shifting system. Gave it more of a direct feel and added some notchiness. Makes my shifter feel exactly like the Mustang's where you can literally feel everything.

 

[mechjames]

I use Redline D4 ATF in my T5 (foxbody mustang), and I'm an Amsoil dealer lol!

 

[69GTX]

From what little I've read on the T3650 it looks like it has the same basic recommendations as the T56. At least in the 2002 version you should have the carbon blocker rings/synchros which should allow you to use some of the basic MTL's like Pennz synchromesh. It will probably always feel a tad notchy no matter what you use, even M1 ATF. Your best chance at reducing that is a non-synthetic ATF (such as the GM MTL/ATF stuff designated for T56's). As Molakule has shown us many times, the dedicated MTL's offer the best wear protection. There's just no guarantee on how your particular trans synchros will behave with any particular ATF or MTL. I've seen hundreds of threads on the subject and there is no one best fluid for each trans. You will find people having issues with any one of them....except maybe the non-synthetic ATFs. I'd have tried the M1 ATF but read a number of threads on it giving more notchiness than the basic ATF's.

T3650 link

LS1Tech.com on T56 fluid

 

[stang5]

I emailed TREMEC years ago about their recommendation for that specific tranny and they recommended Dexron III.... I've been running Amsoil ATF in mine for about 13k miles with no complaints. I drained the factory fill at 5k miles.

 

[69GTX]

Tremec Service Topic from 2003 on recommended fluids

Also read in a few places that keeping level just below the fill hole (-3/4" which is approx 3/4 qt less than factory recommended fill) supports smoother shifting/less notchiness.

Linky

 

[69GTX]

TSB on TR 3650 for 2001-2003 mustangs

Anothe r thread on fluids

 

[69GTX]

RSG on TR3650 See page 3

 

[Linctex]

I have the TR3550 behind a 5.0 in my Ranger.

The "gist" of what I have often read is that the Tremec is a truck transmission first and foremost. People put them in High-Perf Mustangs for their torque handling ability.... but they were NEVER designed to have smooth shifting in mind.

I've owned mine for 17 years, and I've tried every synthetic ATF or synchromesh fluid known to mankind, and it's always shifted like a truck transmission.