Transmission will not move vehicle once it warms up

SOURCE: Changed transmission and ever since then it keeps stalling once warmed up

More than likely something was disturbed accidentally,a connector to a sensor,a sensor itself,possibly even a vacuum line,although a vacuum leak will usually result in a high idle,but an engine that wants to stall,so visually check all these items.At this point,i would do the visual checks,and also scan the vehicle for any possible trouble codes,as a trouble code will point in the direction of the problem.Places like Auto Zone will pull the codes for free.

SOURCE: 1997 Chevy 1500 P/U 4x4 small V8. Transmission shifting issue.

you may be confusing the torque converter clutch engagement with o.d. this trans has a problem with the T.C.C. regulator valve wearing out the valve body bore. this will cause the converter clutch to engage only sometimes or not at all. this will set a P1870 code in the control module. when this code is stored in the controller, ( check engine light may or may not be on), it increases the pressure in the transmission causing the 1-2 shift to be harsh. ask a local tranny shop to scan the vehicle ( most will do this for free) if this is the problem they can either fix your valve body (sonnax parts) or replace it with an upgraded valve body. hope this helps