No Reverse or Overdrive

Hi

1994 F4A22 KM175 transmission no reverse or overdrive

Transmission runs perfect in all gears 1-3....When in park first gear is still engaged and wants to move forward if accelerated and when in reverse first gear is still engaged and will not go into reverse....i guess because first it is still engaged.....Also when in reverse seems like the parking pawl is still engaged

When in neutral the car is in first gear and will go up to a certain MPH then it will seem like neutral till speed comes down

When overdrive button is pressed car slows considerable and will overheat transmission due to i guess first gear not disengaging...

None of these symptoms exist when the vehicle is off wheels move freely in all gears except of course park.......Also this occurred once before and went away but now two weeks later it is back and seems to be here to stay....Any help with a diagnosis would be greatly appreciated!

Linkages are ok as well as fluid...changed fluid no metal parts ect.

Thanks

 

[Terry Posten]

My first guess would be the TCU (Transmission Control Unit). Pull it out and see if the caps inside have leaked. It is under the center console way up under the dash. It is a 6"x7"x2" silverish gold metal box that has 3 large plugs going into one end.

You should be able to get a tested used TCU for around $100.

I would not drive it until you get it fixed though.

 

[Terry Posten]

Oh wait, that is a 7th gen body style right? If so, the TCU may not be in that location.

 

Yeaa checked all that tcu is good...i'm gueesing fluid is either leaking past a seal activating first gear or something wromg with the valve body