TH700/4L60 trans TCC

[robkeith]

Hi brains trust,

i am using a TH700 type trans with a manual TCC switch for the lockup wired through the 4th gear etc.

My problem is that it all works fine when the box is cold, but stops working when box is hot.

Replaced the solenoid at recent service as old unit had slight cracking

any ideas??

 

[MikeC]

Remote chance it might be a wiring problem. On other cars I've wired in a light to come on when the overdrive solenoid gets a signal. Maybe you could wire up something to check the TCC electrical circuit is working when hot.

 

[robkeith]

MMM?? used to work just fine but as box has got older the TCC working has become less and less. Used to work fine when hot at higher speed but not now?? im assuming a pressure drop in the system??

 

[losh1971]

A worn valve body can give problems with TC lock up.

 

[EYY]

Has the temp switch been bypassed?

 

[BlackVXGTS]

13. No TCC lockup: Brake pedal switches improperly adjusted (always on), TCC solenoid failed (easy fix in the pan), TCC clutch worn out (must remove trans and replace TC).

The above item is from "4I60e common problems". Brake pedal switches are not relevant to you because you have a manual switch. Likewise you have just replaced the TCC solenoid. That leaves the TCC clutch worn out as a possible cause of your problem.

 

[robkeith]

Has the temp switch been bypassed?

i believe so, i supplied the wiring diagram from (oldholdens).to the trans builder, and it was working fine 2 years back but with time it now only works first thing in the day when the trans is cold. Im wondering if the pressure solenoid my be causing issues Or the trans is running low pressures although shifts are good no 'flare' on changes