GregElliott

I have an '03 GT with the 5-spd manual trans.
I wanna replace the fluid with stock Motorcraft fluid... which one should I use?
Mercon V, Mercon SP, Mercon LV?
which is for me?

GregElliott

please?

OzzDOA

3.2 quarts of Dexron III/Mercon is what Tremec specs for the TR-3650. Dex III has/is being phased out so it may be hard to find. GM/Pennzoil Synchromesh will work well if you can't find Dex III. Just do NOT put anything synthetic into the trans, synthetics have been linked to softening of the synchro materials causing premature wear.

Chubstang

"TREMEC engineers have recommended Texaco-Havoline Dexron III/Mercon Non-Synthetic ATF. The most recent Ford owner's manuals specify 3.17 quarts of a non-synthetic Mercon ATF. Synthetic fluids will cause premature wear of the synchronizer materials."

cliffyk

This unattributed "Tremec says don't use synthetic" comment keeps popping up, this is from the Tremec 3650 service manual:



I have over 70k miles on my '03 3650 running RP Synchromax (synthetic) with no probelms of any kind...

ym42

Its not "dont use Synthetic", its "dont use GM synchromesh" in 3650 due to a higher sulfur content that might be harmful to carbon-fiber paper parts...