4L80e Harsh shifts

[RPerformance]

2000 silver 2500 6.0L 4x4. shifts smooth when cold once it is up to full operating temp (160 to 180) the up shifts are super harsh, like 6 times that of a shift kit. It does every shift even over drive, there is no slipeage, rpm drop just bangs into next gear. I dropped the pan and fluid was fine, exceptionally clean for 100k miles. new fluid and filter, also no lights on dash or codes. any thoughts?

[silverado122775]

I may be wrong, and could very well be. but it could be that the ecm needs to be reprogramed.

[RPerformance]

anyone know anything on the TCC valve???

also where is the external pressure port for the pump pressure?

[Arrowshooter]

Originally Posted by silverado122775

I may be wrong, and could very well be. but it could be that the ecm needs to be reprogramed.

If for some reason your ECM is raising your tranny pressures, try discontecting the battery for a few minutes, reconnect and see what happens.

Don't know if the 80e's are plagued like the 60e's, but there could be a whole list of opportunities for repair. On mine for instance, when the transmission heated up, say driving on freeway, the check balls would bore into the separator plate in the valve body and stick. This would cause the trans to slip a little and the ECM would crank up the pressure to compensate. Sometimes it felt like I was getting rearended by a Mack truck pulling from a stop.