I am have a 2006 3500 Heavy Duty I just bought and am heaving transmission problems. It happens after I back up. I put into drive and it is like it doesn't want to shift. The Rs will go to almost 2600 RPMs in 1st gear and then shifts straight to third gear with a big slam. And then the same for the rest of the gears. Then when slowing down you can feel it down shifting to almost the point of sliding the tires when coming to a lower gear. When I come to a stop and if I put it back into park and then back to drive again it works just fine. I just changed the Trans Fluid thinking that this would help but it did not.
Has any body heard of this happening before and what can be done to fix this problem?

 

I take it no has had this problem befor.