major problem with 2001

I have a 2001 Suburban that left me stranded. I was riding around 40 mph and rpms went up and truck would not accelerate. The truck would only go about 20mph and really was not changing gears .Engine is running fine but will not move in forward very well and seems that it catches and moves a little bit and then stops moving. It does not have 4x4 and is standard gas V-8. 52k miles

i'd say the tranmission is in limp home mode. get it to a shop might just be something electrical like a neutral switch or tps or there could be serious mechanical damage. check the fluid level and get it into a shop to get scanned

Found out input bearing gave and pretty much destroyed transmission.