Rowdy82

Alright guys i'm new to the Mustang world and 4r70w transmissions. I bought a 35th Anniversary L.E. and it tends to slip just a bit before overdrive engages under light throttle. If i get on in with a decent amount of throttle it doesnt do it. Just when i'm cruising through town at about 35-40 mph have i noticed it. Once it engages in overdrive it doesnt slip or act like its having trouble staying in gear just when it first starts to engage. I'm guessing it to be a worn OD band since thats the weak point anyway or could it be something as simple as needing a flush and filter? Car has 126,000 miles and no other issues shifting through the gears. Thanks for the help.

BLKSTANGER

Every one I have driven does the same thing. Look up the "J"mod it firms up shifts. I will see if I can find a link.

BLKSTANGER

I copy and pasted this off the web.
Modification

The most practical modification for the 4R70W is the J-mod. It involves modifying the valve body separator plate and gaskets as well as changing or removing accumulator springs to alter the shift timing of the transmission. While these modifications can be done to 4R75W transmission, the results are not as dramatic as some of the details of the J-Mod (bigger holes in the separator plate and gasket) were done to the transmission in its design. These modifications are specified by one of the Ford engineers who designed the transmission. It offers faster engagement, quicker shifting, smoother operation, and increased service life. All parts can be bought at Ford dealers for less than $60 including the fluid.