4r55e Torque Converter Locked

[wildmike]

I'm stumped, the other day I was slowing down when I noticed my Rpm drop and my truck started to chug like driving a manual trying to stop without pressing the clutch, the torque converter is stuck in lock-up. I limped it home since I wasn't far but had to manually shift down into 1st and it would unlock. Sitting still the torque converter is unlocked as normal if you put it into reverse but if you shift into D, 2nd or 1st it locks up and stalls the engine how ever if you get it rolling and click it into gear get to 2nd then manually shift to 1st it unlocks? I did some digging online and cant seem to find this problem anywhere, I pulled the valve body out and tested my TCC solenoid its fine I disassembled the valve body looking for broken springs, wear or stuck valves... everything looks fine. Can anyone help me?

Thanks!

 

[sheltonfilms]

Probably should use a scanner to confirm it’s locked up by looking at the slip PID.

But if you are 100% it’s locked up then I would check to see if your Tcc solenoid is somehow getting voltage with just the key on.


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[pjtoledo]

one of the features of that tranny is the ability to enable engine braking when OD is turned off. I don't remember all the fine details, sounds like a good place to start.

 

[sheltonfilms]

one of the features of that tranny is the ability to lock the torque converter by turning overdrive off. its supposed to enable engine braking. I don't remember all the fine details, sounds like a good place to start.

Engine braking is done by engaging the coast clutch inside the transmission. Has nothing to do with torque converter.


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[adsm08]

I am not a trans guy, but I do remember hearing one time, from a guy who was fighting with an Explorer with TCC issues, that Hotline said that the system applies pressure to disengaged the clutch.

If that is correct a failed TCC solenoid could engage the clutch.