I don't think it is your transmission that is causing your problem.
It sounds like it could be the Neutral Saftey Switch.
This is mounted on top of the transmission.
If it is loose or broken, the PCM won't know the correct position of the transmission gear selector, and will cut off your spark at over 4000 rpms.

Pete...


Pete...

98.5 SE Sport Duratec ATX (P66L)
Black Clearcoat on Greystone
DOB 11/21/1997
DOP 12/25/1997
PIAA 510 Super White Driving Lights
SVT CAT-BACK EXHAUST (No Resonator)
DiabloSport Chip (LPQ4) - Engineered To Raise Hell
Too many other mods to list...
Sounds sweet, runs quick...
Crazy Horse Dyno @ 121.4 WHP/129.6 TQ