Lockup of 700-R4

[Lynn D. Brown]

Does anyone know what tells the 700 to lockup ? The ECM ? When is it supposed to lockup. ? My 700, a Mega Raptor from PATC in Shreveport, La ,seems to lock up way too early and bogs the engine. But then, it is using an aftermarket computer (Gen VII+), so perhaps it doesn't even get a signal.

 

[dgoodhue]

The ECM controls lockup, (GM did have an old mechanical lockup for the couple years when the 700R4 were introduced in 82). The ECM grounds the circuit to engage the TCC lockup solenoid (TCC will not engage in first gear). If its always engaging in 2nd, 3rd and 4th gear, someone may have grounded the connection and a simple way would be to put in a toggle switch to break that connection and give you manual control of it.