2004 Chevy Suburban 5.3L V8 transmission type: 4L60-E

[Danielle Pawlenty]

I just bought a 2004 Chevy Suburban with 292xxx on it, I bought it on the 31st of December, everything was fine and it ran good, someone had borrowed the truck on January 11th when they got back they told me it was having a hard time shifting, they said it started shifting hard half way Through there drive. I got back in truck and was like What The **** it was driving like that when I had arrived, asked what they did and he said nothing just drove to pay rent... Now In city it’s hard to get up to speed limit without It shifting hard, and it is running high RPMs, I try to stay under 50mph, if I do over 50mph it is in 3 1/2 damn near 4RPMs. I did a transmission flush the fluid was burnt but Barely any metal in it. I added half a bottle of lucus stop slip, it seems to be catching in 2 1/2 RPMs if I’m very light on the gas pedal. If I am hard on gas pedal the RPMs go high and the transmission does not catch.. Please, any suggestions I’m completely confused with this one..

[davester]

maybe see if there are any transmission computer (TCM) codes?  major parts stores generally have scanners that are good enough to read tcm codes, as the basic cheap code readers don't.