Ok so long story short i jumped on it tonight and it shifted and started going good then when it was about to shift once it got higher in the rpms it ended up not shifting but almost jumping the rpms up and down until i let off(wasnt the rev limiter or anything like that either) then it shifted fine and kept going so i tried it again and the same thing happened dont know whats up with it trans was replaced about 5000 or so miles ago and all the fluids are good. Also noticed that when shifting sometimes it has a hard shift to it where it thumps the truck pretty bad but sometimes it will shift perfectly. any helps appreciated need to get this figured out. just some info on the truck its self it has 5.38 gears pretty much new auto trans 44 tsl's edge chip stage 1's and straight pipe

 

I have tranny issues similar to this and it usually winds up being the Vehicle Speed Sensor (VSS) in the rear diff. If it's fairly new, you can remove it, wipe the gunk and metal shavings off and reinstall it. If you're not sure how old it is, replace it.

Before replacing, check for codes and have them cleared. That way you'll know for sure if they come back after corrective action is taken.

Also, with that much of a difference in tire height, did you recalibrate your speedometer?

Check all the connections and wiring you can for proper seating and cracked/broken wires. You'll need to check from the VSS forward, unfortunately. Check the connections at the tranny, too. Sometimes a connector pin will get bent or misshapen and not make a good connection.

 

alright ill check that. trucks down right now anyways with a cracked rim
i use my gps for my speed never did the speedometer.

 

This may sound silly but you need to check your brake lights, high mount included. They are in a relay with your cruise control and torque converter. If you have a brake light out your torque converter will disengage and bump your RPM's. You will also get hard shifts.

Good Luck