Tmello401

Hello Everyone, I have a 1996 12v Cummins with 193k on the clock. The auto transmission got rebuilt around 60k ago. Over the past year or so I have been notice when the truck is warm and I come to a complete stop like a red light, getting going can be hard and it takes more Rpms than it does normally. When cold it is fine, when it is warm sometimes it doesn't do it and works fine, so it is intermittent. Typically the Rpms go up to a grand and I go fine, when it's slow, I'll go up near 2k and when not on the brake it won't even roll forward. Once going the truck goes and shifts through every gear fine. It does pop out of OD but I did replace the TPS last year. Also I replaced the TV cable. Transmission fluid is clear and got changed with filter last year. Any input as to why it can be so slow to get going would be greatly appreciated, thank you.