[Drooopy33]

I have a 2003 Denali, the truck sounds great but when driving car revs high and doesn't sound like it wants to shift u till I let off the gas. Also doesn't feel like it wants to go higher than 3rd or 4th gear. I get up to about 40mph and it rpms raise high and it will not shift. No check engine light or codes are being thrown. Transmission fluid is full and doesn't smell burnt or anything. Any ideas other than to flush and see if that helps out, or if it a common problem that something has faulted...thank you for the help!