2001 Dodge 1500 four-wheel drive 46RE transmission pulls strong for 30 or so miles then will start slipping. When it starts to slip I can come to a stop shut the truck off for less than 1 minute start it back up and the truck will drive for another 30 or so miles with no slipping and then it will repeat the issue. Any advice on what could be causing this issue would be greatly appreciated TIA. Also I have already changed fluid and filter thinking the filter may be getting stopped up. But the issue persists.

 

Sounds like the issue may happen once the fluid warms up. Has the check valve in the cooling line near the radiator been bypassed? See this thread for details - https://dodgeforum.com/forum/2nd-gen...46rh-46re.html

You can also check to see what the temperature is of the transmission pan when the problem occurs with a laser temperature sensor to possibly help narrow down the issue.