When i drive my truck between 40mph-48mph the rpm's surge up and down 200 rpm's or so. It feels like torque converter locks and un-locks once i'm at 50 mph and up no problem or below 40mph. Could the overdrive torque converter mph lock up be to low? I feel all the gears and at 40mph its in overdrive at part throttle and the torque converter I thinks locks. Computer seems confused and locks and un locks the verter. If to low what do you guys have your set at? Thanks

 

I have the exact same problem At about 47mph it cant decide if it wants to be locked or not. Very annoying. I'm still trying to work it out. Its all in the tune.

 

This is very annoying i would try to ignore it but you can hear it. That cant be good.Anybody else......

 

I have a similar problem. Something else i've noticed is that when I begin up small grade it will lock up and rpm's drop. Get to the top tc seems to unlock rpm's rise again. Trucks been tuned by westers. Spoke with them last week. He recommended a CASE relearn Crank Angle Sensor something due to misfiring. Said the dealership can do this ($$$). Haven't had a chance to call for a price. Guys over in the tuning section seemed to think it might me a TCC lock/unlock speeds vs. Thorttle position vs. Gear issue.


Here is a link to my post last week.
https://www.performancetrucks.net/fo...d.php?t=371775

Be interested to see what your problem is. Good luck.

 

I had the same problem.
TC was locking way too early and not unlocking easily enough. It was almost as if the trans was desperately trying to keep the converter in lock.

It's definately in the tune. The day I tossed the mail order tune and got on the dyno was the last day I had to deal with that!

If you dont have an SES light you don't need a crank relearn. Either deal with your tune (er) or go to a qualified dyno tuner. You'll not believe the difference a good tune will make.

 

it is in the tune move up the vert lock up about 3 mph

 

I'm going to try to move up the speed, thanks hope that i can eliminate that...

 

Trever1t- was your locking when it sensed an increased load or driving up a hill or whatnot?


No ses light here.