I have a 1999 Bravada, when driving at highway speeds (60-70) I notice the rpm's going from around 2000 to around 3000 and the engine whining. If i tap on the gas it will shift back, rpms drop for a few seconds then race back up. I have changed transmission fluid, filter. Also note it does it about 90 percent of the time. Doesnt seem to matter if its hot or cold, either. Has about 89,000 miles on it. Any, Ideas would help.

 

i am a mechanic but not a trans specialist,my 2000 bravada was doing this and the tranny shop i use replaced a pressure sensitive switch in the trans that controls the lock-up in the torque converter.mine would do it between 50-60mph but if i traveled 75 it was fine or slower.