I have a 1995 ram 2500 cummins with an automatic transmission, I got this truck recently and still don't know much about it, but what I did notice is even at 50 mph I'm at 2k Rpms.. Which would be 3rd gear. What I'm wandering, is this normal? Is it a 3 speed? Or is it a 4 speed and it's just not shifting into 4th?

 

Sounds to me like you don't have any overdrive your trans should be the 47rh which is a 4 speed trans with converter lock up.

 

Guess not, because even the O/D switch on the dash doesn't do anything. But it does light up.