so i recently bought a 2004 suburban about a month ago. within a week the transmission went out and the dealership put a new one in. it took them 3 weeks to do it. so now i have the rig back and i have been driving it for almost a week now.
today i spent most of the day driving and everything was fine, but tonight when i was on the way home from picking the wife from a work function the rig all of a sudden starting having shifting problems like before and just to maintain speed and momentum i had to hold 4,000 rpm or redline.
got home popped the hood and i could smell burning rubber and burning oil but the belt was fine and couldn't find a hint of a leak.
one website says that i could have a bad ecm/pcm, however i would like other opinions or confirmations on the problem

 

I'm assuming they installed a reman. They could have just stuck a used one in it unless you have proof otherwise. Sounds like it was slipping really bad. They should have replaced the everything associated with the external transmission cooling system. Radiator, cooler in front of the radiator and flushed all the lines. I would take it straight back to them.

 

Back to the dealer you go. Good they are trying to takecareof you.