Transmission/ electrical? problems Diagnostics

[hondo]

Alright, here is my situation. i have a few problems with my car that are septate but i think all from the same source.
NO 4th Gear
False neutral when shift knob is in D.
Tach not working on occasion. (when on the brakes)
TCS light on.

I have had the problems for a while now and until i noticed the tranny they havent bothered me too bad. I really only noticed the tranny becdause of a recent road trip. (I never go on the freeway so i never use 4th gear) my RPMs were waaay to high and it would go into a false neutral whenever i would let off. and i got terrible gas mileage so it got me wondering what was wrong with the car and i have no overdrive.

Im thinking electrical. what about you guys? the tach and tcs act up when i go through a puddle or its raining outside and the first time it ever happened was right after i washed my car.

Any opinions? similar problems?

[FordMan77]

The lack of 4th (overdrive) and "false neutral" sound like the 4th clutch hub is stripped and you lost OD. If you manually drop it into 3 do the RPMs change?

On the tach/TCS issue I would check the harness for loose/bare wiring as it sounds like it's grounding/shorting out and causing issues.

[hondo]

if i put it into third the neutral problem goes away. but i already replaced a tranny a few thousand miles ago andit has less than 100k and has never had a problem.