I recently acquired a 2007 1500 Dodge Ram 4x4 HEMI running on 275/60-20 tires (don't have a clue as to what rear end ratio). Anyway, when I take off normally and set the cruise to 59 MPH (via both speedometer and GPS) the tachometer will read 1850 RPM which I thought seemed somewhat high. If I accelerate up to approximately 63 and then let up the speed will go back down to 59 MPH but the tach will go down to 1600 and stay there until I stop for some reason and then start again. Once I normally start again an hit "resume" on the cruise the speed goes back to 59 MPH and the tach again goes up to 1850.

When I accelerate up to about 63 and then let up to get the tach to go down I do NOT feel the transmission shifting. Anyone have a clue what, if anything, is going on that shouldn't be?

Don

 

My truck shifts pretty obnoxiously (usually when I don't want it to) I think you might want to get it serviced

 

you might want to change your tranny fluid and filters before anything. its a less expensive way than going to the shop and paying a few hundered or more dollars for them to tell you the same thing. how many mile are on your truck?

 

My numbers are skewed due to my SuperChips but at 50 im at about 1500, 60=1600-1650, 70=1750 and 80= 1900. This is in 5th gear with a 3.92 rear end. But I'm coming on 36K so I need to change my tranny fluid and filters soon. But my cruise control tends to jump the RPMs around a little but they settle back down to those numbers after like 5 mins

 

Approximately 65K. Changing the transmission fluid and filters sounds like a good idea but in all of the vehicles that I have ever owned this has never been done and all has been well (except one and that was at 30K). Heck, I also have a 1995 V10 with 130K and the fluid and filters have never been changed.....maybe I should do that vehicle first.:-)

Don