Why does my '97 Chevy Silverado transmission shift hard when it gets hot?

[Rob]

I recently dropped the pan and replaced the fluid and filter. I think it's a 460LE transmission. It mainly shifts hard after a long highway run at near constant speeds. Any suggestions? Thanks!

 

[george 2]

see if you need to add more transmission fluid

 

[ttompetty]

Check The Fluid Level While The Vehicle Is Idling,, Does The Fluid Seem Brown Or Smell Burned.. When U Replaced The Filter Are U Absolutely Poitive You Have The Filter On There Tight, Did U Replace The O-ring Or Rubber That Comes With The New Filter If It Did,, If Not Or Your In Doubt You May Have A Slight Leak As The Filter Is Trying To Draw Fluid Up,,,art.. Also,, Im Sure U Did Check That U Have The Correct Trans Fluid....

 

[Gene B]

sounds like cooler line stopped up to a certain degree. if fluid does not get cooled down enough will be too thin to work properly.

 

[mac]

Might be the temperature sensor/switch.