Torque converter always locked in 1st gear

[Spinnas]

Truck is an 04. 5, stock everything. I was towing my trailer last weekend and took off from home with everything normal. When I reached my destination(3 hour drive), I was slowing to a stop and the truck seems like it didn't want to stop. The torque converter was locked in 1st gear and wouldn't unlock. On the drive home, it was locked in 1st gear when I left and locked when I got home. The truck runs and drive fine outside of 1st gear, it unlocks shifting into 2nd, locks if I have it manually pulled into 2nd in tow-haul, unlocks shifting to 3rd, locks in 3rd, and locks in OD. Ideas of what may be the problem? Haven't checked for codes yet, no CEL, trans fluid looks fine.

 

[cerberusiam]

If the clutch has locked the truck won't stop without some very noticeable results, like jumping off the ground. If it is just hard to stop and wants to pull thru the brakes the TC has failed internally.

 

[Spinnas]

It wants to drive through the brakes, but I can get it stopped kinda. And not sure if it makes a difference, but when I say it's locked in 1st, I mean it never unlocks at ANY time in 1st, not just at idle while trying to stop. So when I would take off from a stop it would bog and start to pick up speed, and when it would shift into 2nd at 20-ish mph, then it would unlock and act normally. Shifts fine and locks/unlocks like it should in 2nd-4th, just not 1st. And just asking, if the TC has failed internally, wouldn't it be the same in all the gears and not just 1st?

 

[cerberusiam]

There is a sprag clutch on the stator hub that fails. When it does you have a no stall converter and it shifts early trying to leave from a stop and tries to pull thru the brakes once it is up to 25-30 mph it works normally.



If the truck tries to pull thru the brakes in reverse and forward gear, almost always will be in 1st gear at a stop, that is likely the problem.

 

[Spinnas]

I forgot until now, but yes it does it in reverse as well. Thanks for the info, makes sense now.