I searched but didn't find any related posts. I have a 2006 Dakota with 4.7 and the 545rfe auto transmission. It's been used to tow on a semi regular basis, I've added an external cooler, a transgo shift kit, and changed the fluid & filters every 30k with the good stuff.

At 142k, it started acting up. When cold, I put put my foot on the brakes and shift into reverse and sometimes it would choke off the truck. Other times after warming up, if I come to a stop it will do the same sometimes. It shifts up and down fine. If I'm coming to a stop and it starts to lug, I can cycle the brake pedal and whatever is stuck will release the clutches and it will idle normally.

I took it to a local transmission shop. He drove it and said the solenoid packs are known to go bad. He replaced the solenoid pack, changed the fluid & filters and it ran like new until this week at 146k and started doing the same thing.

The fluid is bright pink with no evidence of water, overheating or varnish. It shifts and drives great. The issue is lugging the engine when first shifting into gear, or coming to a stop quickly. Pumping the brake after the truck downshifts to 1st, but before it comes to a stop seems to jog something and release the pressure. No error codes.

 

Just a follow up. The problem turned out to be that the friction material for the lockup clutch in the torque converter was coming apart/loose. The first guy cured the symptoms for a while when he changed the solenoid pack and changed fluid. The second place cut the torque converter apart and said the friction material was coming loose and falling apart. He replaced the torque converter, cleaned out the cooler, and put a master kit in the transmission. It's all good now. I just paid for a full rebuild in 2 steps....,