I have a 03 Durango SLT, with a 5.9L, 4x4. It doesn't want to shift out of 1st gear unless I let off the gas. When I let off the gas and it shifts, and then I try to get into it a little too heavy it will drop back down into 1st gear and stay there until I let off the gas again. When I'm up to highway speeds and going up a hill or want to pass someone it will drop out of overdrive, but I think it shifts too fast into overdrive again. Once I do get it to shift from 1st gear I think it shifts too fast all the way to overdrive, but that may be just me.

 

You didn't say how many miles on your D. Do a trans service ( change the filter adjust the front and rear bands. Check the adjustment on your TV (Throttle valve) cable.
The band adjustments and filter change at 40 to 60K is the best maintenance for your D.
Let us know.

 

I have 104,000 mi on my Durango, and I changed the oil and filter about 6,000 mi ago. I was thinking that it may be out of adjustment, but with all of these new electronics they are using today, I really wasn't all that sure. I will look into these adjustments, thanks.

 

Change out the TPS.