HI All,

My TCC has been acting up intermittently. When towing my fifth wheel (6000lbs) and I have the accelereator pressed down 1/2 or better(line pressure higher), the TCC will unlock/Lock and the TCC pressure as taken off the cooler line pulsates as well, engine rpm surges.

Some Background first:

1) I Have pressure gauges in the cab reading transmission line pressure and TC lock pressure in the tranny cooler line.

2) I have a TC unlock/normal/Lock switch installed, and also a TCC lock indicator light which tells me the signal is given to lock the solenoid eletrically, either with the switch or PCM

3) Fluid has been changed last winter with new ATF+3 and filter installed in cooler line.

The TCC will do the puslsating with the switch selected to lock, or normal with a steady lock light on both selections.

It will not happen all the time, If I unlock the TCC, then relock (like going down a hill, the TPS will unlock the TCC, or just using the switch) it will not happen, then next time it will do it again

I was thinking the TCC solenoid may be weak(high line pressure with the throttle pressed intermittently unseats the tcc solenoid valve, it vents, unlocks the TCC, and then reseats due to the lower pressure???) or some crud in the line, and some time it seats properly, sometimes it dont...

It is not an electrical signal problem as I can bypass those system of control, But it could be the solenoid or internal Tranny hydraulic TCC circuit problem?? I know little about how all the TCC valves work in the tranny...


Anyone had this before, or can provide insight?

Thanks Abunch, Cheer to all.

 

I managed to sort out what was going on,

It was a weak solenoid that was unporting at higher line pressures' induced by the throttle pedal boost valve combined with the towing of te fifth wheel.

The solenoid was not at fault, but I did put a a current sense relay inline with the TCC solenoid which brought the resistance from 30 to roughly 70.

The relay worked a TC lock light, I may have to come up with a better system

anyways, I lost my light setup, but it does not do the "tc dance" anymore....