TQ Lockup

[graysilverado5.3]

Ive been having trouble with my lock up during normal driving. Before I had the tb stall it was not that noticable, but now with the new stall, it is bad. The tq locks and unlocks between 45-55 mph. What causes this? And how do I fix it? Would I have to drop tranny to get fixed? Thanks

[Circle-D]

Sounds like it might be the tune. Get a scanner on it and see what the computer is commanding. If the computer is telling it to cycle, then you need a tune. If the computer says stay locked, but it is not. Then need to go into the trans to see what the problem is. Solenoid, valve worn or maybe even the converter.

Chris

[oleshifty]

My blazer does that. Locks/unlocks constantly going 45-55. REALLY annoying. I THINK mine is supposed to though.

[petey62782]

Most converters are programed to come on at 47 mph minimum so it drops below that it might disengage so it's either programing or maybe your lock up solenoid if it comes in to hard then it sounds like the PWM solenoid is either programed wrong or no good hope this helps

[graysilverado5.3]

I know for sure its not the converter. I guess i'll have to take my truck to my tuner and ask him to check it out, if nothings wrong with the tune, I assume its the solenoid thats bad then. Would I have to drop tranny to change out that solenoid? Thanks for the help!

[petey62782]

Most of the solenoids can be accessed from dropping the pan and there on the valve body but some like the TCC solenoid you have to drop part of the valve body because it's all one wire harness it's hard wired into no disconnect clip but most solenoids are plug in clips