Originally Posted by
Stewart_H
The only manner in which I'm familiar with the term "coil pack" is for the COP's (Coil Over Plug) found on the Ford modular gas engines, like my Lightning. When you keep using the term coil packs, are you referring to individual coils within the solenoid pack?
Stewart
Yes a coil pack is a set of solenoid coils that will turn off in combination when the signal is sent from the PCM. The coils have 4 states.
1 off 2 off
1 on 2 off
1 off 2 on
1 on 2 on
These conditions are what determines what gear your transmission is in. If I remember correctly fail safe is 1st and 2nd. I don't remember which solenoid conditions will cause this but probably 1 off 2 off and 1 on 2 off.
The inputs to the pcm are the speed from the reluctor mounted on the diff and the oil temp. The tranny oil temp will cause a change in shifting until the transmission warms up. Some mod and take this out.
The selector mounted on the DS rear of the transmission is the manual power selector that will allow the driver to shift manually in 1, 2 or 3rd the button on the shifter of course is OD.
There are only 2 ways the coils can fail. Open/burn out either of the 2 coils or have the solenoid plunger fail. There is also an update coil pack which I had installed last year when I had a total rebuild on mine.
SO given no internal transmission issues. Items to cause your problem are:
1) coil pack
2) switch on the side of the transmission TSR I think it is called
3) wiring or plug issues
4) PCM This was my problem and expect even with a used one to cost around $700 to $1000
NOTE if you buy a used one dont' trade your old one until a locksmith has transferred all the security information. Make sure the VIN numbers match any PCM you install. Buying new from Ford direct will help avoid this problem.