47RE - My TC Lets Go, Should It?

[DougJones]

My torque converter is letting go and letting the truck free wheel when slowing from highway speeds. It comes unlocked at 45 mph and the engine drops to idle. You can feel it let go and I have to add just a little more brake to slow down. Or, when driving in areas where speeds are less than 45 mph, if my foot isn't pressing the pedal, then the rpms are just at idle. It doesn't do this if I have the OD turned off.



Is it supposed to do this? I'm almost certain that it didn't when I first got the truck!



I haven't had the flash done yet that corrects shifting so that it shifts to fourth at less than 70 mph when at half throttle or more. Would this fix the TC letting go problem too?



One other tidbit. My TC seems to slip too easy. I'm running a Bullydog Downloader and the Outlook Monitor, but even in the tow setting and the power adjusted to 0% the TC can slip accelerating uphill with just a 1500 lb trailer in tow if I step on it very much, but not enough to come out of OD.



Any advice would be appreciated.

 

[Suprmn]

sounds pretty normal to me. I have an older truck with a 47re and it operates pretty much like you describe as far as the torque converter unlocking when coasting. However, the torque converter is not suppose to slip. I would verify that it is indeed slipping and if so, do something about it soon before it overheats your transmission or clogs it up with clutch material.