I have a 2003 5.9 3500 that has had a new (rebuilt) tranny within the past year. Lately it acts as if can't decide 1st or 2nd (or 3rd) as it seems to want to shift back and forth at low speed or idle. Secondly, it seems to lack power around 23-24k rmp. Any thoughts as to what could be the problem?
Have had conflicting and confusing answers....

 

I also have a new tranny the guy put a heavier shift kit in it and what I have noticed is at low speeds 25 and under it is trying to get into the lowest gear possible due to the shift kit. I am going to have someone replace it with a stock shift kit I think that will fix my problem. Could this be the issue yours is having?

 

The tranny was rebuilt and installed as a replacement by our local garage here.....it was a stock install.....Thanks for the idea, but think not

 

Governor pressure sensor.

 

Thanks....will explore that option!

 

Post the results when you find out what it is I'm interested since I'm having the same trouble.

 

Will do......good luck!

 

Well since the last post, have been to the Diesel repair guy and this is what he found....
Because of the erratic behavior the tech suspected that it was the governor pressure solenoid, as 06RAM 2500 predicted. He removfed the pan and inspected the magnet for filings and junk, and discovered a piece of broken front servo cover snap ring. He adjusted the bands, replaced the filter and Governor solenoid and on re-road test, found that the throttle pressure cable was set wrong....he adjusted the throttle pressure cable and the road test was OK...
Seems like the problem was the GPS as suspected, along with a few minor adjustments all is well.