Here is a little back story for my 4l60e. Truck has about 30k on it now and last fall I did a cam swap and sent the pcm to get tuned. When I got some seat time I noticed the lock up couldn't make up its mind and unlock/ lock pretty regular basis. I had to send the pcm/ tcm back to get the speedometer recalibrated for the soon to come gears and asked to see if we could fix the indecisive TCC.
When I got the pcm/ tcm back, installed the 4.88 gears I would have to throttle up to engage the TCC. Also when the converter would lock it was such a positive engagement it felt like a 5th gear which I thought was just me “feeling” more due to the gear ratio. This went on for a little while and it seemed get more difficult to engage the TCC since the unlocked RPMs and locked RPMs were so close.
I called NP about the TCC engagement they said to send it back and it was no problem. I have been putting aside cash to buy a HPT from them to avoid downtime. Recently a new symptom has appeared that makes my think its not the tune. Wide open throttle onto the highway then going to cruising speed it will not engage the TCC no matter what I do. I can play with the throttle, slow down doesn't matter no lock up to be had.
This morning I tried something and got on the freeway hard. As I expected the converter would not lock up and then the MIL came on for a P0741 code (lock up solenoid stuck). I cleared the code and then I got off the next exit and came to a complete stop. I got right back on the highway nice and easy and bam TCC engaged with no problem. I checked my fluid when I got to work and its right where it needs to be. Any Ideas?