I bought my 2007 1500 Ram used with only 2500 miles on it. I was very excited to have a new truck until a week later it started with major issues. It wouldn't shift out of 2nd gear. Two dealerships and four visits later they finally replaced the computer which fixed the problem.
The issue I am currently having is that I have to turn the O/D off until I get to about 50 mph or2500 rpms. If notit bogs down and makes a grinding noise. Sometimes it will even shake at around 35 mphbecause it is idling so low. It always wants to shift to the highest gear no matter how fast you are going. The dealership says this is normal. I realize it is only a four speed but should it be running so rough?

Thanks for your input.

 

check the fluid level of the trans itself if its accessable if its low or non existant that could definately be creating an issue - take it back to the dealer have them run a diagnostic test on the trans itself, you say you just bought it should still be under warranty