Hello, here is the procedure to adjust the bands. It is usually a leaking lip seal that will cause clutch slippage,
The front (kickdown) band adjusting screw is located on the left side of the transmission case above the manual valve and throttle valve levers.
CAUTION: If Adapter C-3705 is needed to reach the adjusting screw , tighten the screw to only 5 N·m (47-50 in. lbs.) torque.
The transmission oil pan must be removed for access to the rear band adjusting screw.
I hope this helped if so an accept is appreciated
I do not think you have a torque converter issue, that would be a completely different set of complants.
Lip seals are not serviced with the pan off. They are attached to the clutch pistons inside the trans.