High Rpm....low speeds

What is your rpms at 65 mph

 

Well if the RPM is higher at a given speed now vs before, the clutch has to be slipping.

Either that or your speedometer or tachometer are giving a false reading.

 

Well now I read the part where you state the RPM is higher at those speeds when loaded vs bobtail. Clutch is slipping.

 

That sounds pretty close to where it's supposed to be for low pro 22.5 tires..

 

Every truck/trans is going to be different, my truck with an 18 speed and 3.55s runs/shifts different then my uncles 15 speed with 4.33s which is different from the rto 13 speed with 5.13s. You more then likely bought a fleet truck that was governed at 60/62 for mpg, how bad is/was the clutch did they actually do the clutch the first time or adjust it and tell you they did it? Might need another adjustment if you are starting off in a high gear.

Sounds like you bought the wrong spec truck for what you wanted, did you have a good year? Take the write off and swap in an rtlo 13 speed and some taller rears that will work better with Your engine/load/terrain

 

Ok you've started another thread like this in the past 4 or 5 months. Is it the same issue or is this something new? I know you've deleted the truck and the transmission was swapped out to a different model. Did you ever get the parameters in the ECM verified to see they were set up correctly? Did you ever bother to look up the transmission ratios for each gear and plug them into a calculator like @singlescrewshaker posted? That'd tell you right away if this issue is related to the wrong transmission being installed or if its an issue with the ECM program from the delete. Hell if the transmission was changed there could be the wrong tone ring on the output shaft and its giving the wrong signal to the speedometer.

You really need to include all this pertinent information if you want to resolve this problem. Half stories will get you nowhere in solving this.

 

Think I got swindled.....transmission

In case somebody can pick up on something that might have been overlooked a few months ago.