Help, 2006 4.7 Ram SLT, Auto 2WD, Cruise works fine on level ground. If you have any upward grade, it doesn't stop working but the truck's speed slows down a lot more than it should. Once you get back to level ground, it will hold it's speed until the next incline. I have replaced the brake pedal switch (Mopar, not aftermarket), still does the same behavior. No codes showing, no check engine light,ect. Any suggestions? Thanks in advance.....

 

Let me guess, you've got 3.55 gears in the axle. The 4.7 needs at least 3.92s to handle the weight of the Ram, otherwise, it will do exactly what you are describing.

 

It is normal. My 2500 with 33's and 3.73 gears and Hemi does the same thing. It is due to weight. Turn OD off and run the hills that way. You can turn OD back on for the flats and smaller hills.

 

Thanks, the truck is actually at college with my son, as soon as he gets back with it I'll try that. It makes sense from a physics standpoint, but it going to make the MPGs suffer running w/out OD....

It has the stock 20" wheels and gets about 16 MPG on flat highways at 65-70 mpg. I guess it will pull well for the 0.4% of the time it will have something on the hitch. Thanks for the information.