Originally Posted by SSedan64
Did the TCI lockup kit come with a manifold Vacuum switch? If so it may need to be adjusted.
If the Brake Light switch is out of adjustment it can also cause this. Try holding the Brake pedal up while driving & see if it stops.
Bad TCC Solenoid or worn/leaking TCC Apply Valve in Pump are other problem areas.
The TCI switch tested at 6" of vacuum.
I've checked the brake light switch (working) have held it up as suggested, no difference.
" worn/leaking TCC Apply Valve in Pump " Where is this located and can it be checked, repaired, replaced by a competent transmission shop? Would the pump need to be replaced?
Drove it to Tulsa, Ok. yesterday to drag races, 120 miles one way. Lockup never occurred going up there. On the return trip it engaged and stayed engaged once at bout 75 Mph. Using the switch on the dash I could engage and disengage it at will just for that period of time, bout 10 minutes.