my 4R100 is pausing after idling and going from park to drive and second. Going from part to reverse is fine.
Fluid is Mobil synthetic w/ about 1500 miles on it.
Towing 15K and the temps never exceed 170F even when it's 110F ambient.
Have 6.0 cooler with external filter, no debris in filter or tranny plug.
fluid level is fine.
I had the same initial thought.... But once it engages the tranny is flawless. Even pulling 13k lbs up 6 & 8% grades the temp never exceeds 170F. The fluid is clean as a whistle. I've pulled the external filter, cut it open and it has no particles in it to worry about. The magnetic plug is spotless.
I have a Superchips tuner that I use to read DTC's. I also have a U380 Ford ODB2 scan tool to back up any codes that may be read or miss read. There were no codes.
After several hours every day, I have found the the most common cause of the tranny issues I am have are cause by main shaft bearing failure. My current failure isn't enough to register a code due to low pressure.... yet. By the time the failure or low pressure situation is bad enough to register a code, the truck would no go, in any gear.
Solution... Rebuild tranny.
Not worth partial fixes. I've never been towed and (nock on wood) never will.