Hard shift after warm up

[ManitobaMudMan]

02 6.0/4l80e question.
The truck shifts fine when its cold, until it gets a little bit warm on the transmission temp gauge. What could the problem be? Just replaced the rear main seal and put fresh trans fluid in her.

[ManitobaMudMan]

Also I can pinpoint the time it does it if im driving down the highway. The rpms will increase about 300 rpm. Tourque converter?

[transbuilderguy]

sounds llike the good old TC slippage have it scanned most likely there will be a trans slip code stored if so then the reason forthe hard shift is due to the pcm commanding max line pressure to the EPC to try to stop the slipping.

[ManitobaMudMan]

would it pop a CE light?

[transbuilderguy]

yes it can sometimes it does sometimes it doesnt depends on the frequency of it

[ManitobaMudMan]

its never put a code out, but just by reading on some other forums sounds like a simple tc swap will cure it?

[transbuilderguy]

most likely not because its the valve body that causes the problem the torque converter failureis just a symptom.

[ManitobaMudMan]

ah gotcha, simple fix or no?