The tranny in my 2003 2500HD has stopped shifting when I punch the pedal to pass. It will shift if I pump the pedal a couple times for each new gear. The symtom is I mash the pedal, the engine goes up to about 3 K RPMs and the tranny just stalls. Its dangerous if you are trying pass and there is oncoming traffic. For normal driving with no demand it shifts normally. I haven't tried it with my fifth wheel yet.

Any ideas?

Change the fuel filter first to see if that resolves the issue.

Brian

X2 Change the fuel filter. :D