Hey everyone. I have a 4r70w tranny and have always used Mecron because thats what was the factory recomendation. I looked on here and everyone is saying go with Mercon V and was wondering is there a reason why? Am I hurting my tranny with just Mecron? Thanks on advance.
For the start; Mercon V is not the same as Dexron III .
'96 and up T-Birds & Cougars with the 4R70W use Mercon V. It can be used in the '94-'95 cars, but it is not recommended by Ford. Mercon-V is a semi-synthetic ATF, introduced in 1997 for use in vehicles equipped with the 4R44E or 5R55E transmissions. The '98 model year 4R70W transmission, AX4S and AX4N transaxles use Mercon-V.
TSB-98-8-8 states: "Mercon-V is not interchangeable with the current Mercon service fluids. Using the incorrect fluid may cause transmission or translate concerns."
When asked why? Ford responded, "The synthetics work their way past seals and cause leaks and/or durability concerns". "The 1998 transmission seals are updated to prevent these problems" - Dayton Ford Service Technician.
The Shudder problem [TSB 95-23-4] is solved and your driveway will be dry as well. The synthetics actually prevent the ATF from flashing [burning] and this heat is what causes the TC to shudder. It's more shudder resistant because among things, it does not contain ash. If you really want to eliminate the shudder, install a new stall speed convertor one with a larger pump.
Aside from this, it's wear properties are much better than other versions. It can stand up to temperature better (and if you ever looked at the trans temp a t-bird runs, God help it).
It has a downside, which seems small, but when you make 1.5 million trans's a year it's big. It is a pretty big skin irratant. If you change your own fluid, or work with, wear laytex gloves. Some people react to it, and some don't. No reason for you to take any chances. A-Train