Auto Trans won't move

[norcalram]

Truck has been parked for a bit and now I finally have time to get it going again. It started out having trouble taking off from a stop, needed a bit of extra throttle to get the converter to engage, usually the first stop of the day. After that, she ran fine. Didn't drive it for a bit and last time I went to move it, had to give it WOT to get it to creep along. Truck has 106,000 and transmission was replaced at 54,000 for nearly the same issue. I have searched for days but can't seem to find anything similar happening on here. I don't want to keep replacing every 50,000 miles but I don't want to just start throwing parts at it either.
I've put the computer on it and it's not throwing any codes. I was thinking either valve body or govenor or the TC was draining back. Any help would be greatly appreciated!!!

 

[fest3er]

Start it, put in neutral (which allows lube to flow; park blocks flow), rev to 1500 for 30-60 to refill TC. Drive. If it's OK, you likely have a drainback issue. If it's OK after the initial startup problem, this is the most likely problem.

Food for thought: You could have low lube level (trans will be sort-of intermittent). You could have drainback (wait for lube to refill places it drained out of). You could have low pressure(s) (not enough pressure to [fully] engage clutches/bands). Less likely, you could have 'guck' blocking ports in the VB. Even less likely, the filter might be clogged (preventing adequate fluid flow, but this should manifest as a trans that works for a while, then gives up).

 

[norcalram]

Thank you for the input, I should have noted that prior to the last attempt, when it was dead in the water, I replaced fluid and filter and upgraded to a deep pan. I was hoping it was just a fluid issue, but that didn't make any difference. I've run it for quite some time in drive and N prior to shifing to drive or reverse to no avail. If the valve body was gunked up, could that cause the failure to engage completely? Possible the governor is clogged also and not allowing sufficient pressure?

Also, not sure if its related, but I noticed that my cruise control won't activate since that time also.