[sick472]

Thanks for the quick response PJ!,

No tach in the truck, but I am 99.9% sure the lockup is not happening. It does have all the original wiring for the 700R4. The only exception is that there is no EGR solenoid to be found, but I think the wires are there. There is a third pin in the connector (in the "D" position) of the original wiring and a pin in the transmission to correspond to it. The close-up, below, closely resembles what I have. Maybe, with the exception of the two case grounds . I am going to make sure there is a wire for the "D" pin in the harness this evening along with the continuity check you mentioned. I believe this "D" wire would have gone to the EGR solenoid. My transmission man has suggested that I ground the "D" pin wire as I am going down the road to see what happens. That sounds kinda iffy to me just because I haven't wrapped my head around how it works just yet, but I am glad to hear you say similar.

IF grounding the "D" wire while in 3rd or 4th gear causes the lock-up to function...would it need to be on a switch to disable it or could it just be grounded permanently? I don't want a switch to forget about and cause any damage.

The reason I ask is that the vacuum pod has not shown itself to go open yet under a low vacuum event and the circuit will likely be live upon deacceleration (aside from braking). I wonder if the "D" pin was used for a computer to switch the ground wire open and closed?