I've got an early '03 2500 SO (purchased 12/'02), which probably has the 47RE tranny, though I haven't confirmed.

The truck has been fantastic. Now 63k miles with no problems. Only regular maintenance items. Good mileage at 20 empty on highway and averaging 17 or 18 in the commute. Towing gets between 11 and 13. No complaints, just one irritant:

When towing (I tow about 9000 lbs regularly) in cruise control the vehicle will REALLY bog down on a hill before dropping out of overdrive. For example, I'll set the cruise control at 75 and it will slow down 12 to 15 mph going up a hill before it will drop down out of overdrive.

I've got some friends that have a second gen diesel ('01, I think) and theirs doesn't do this. In fact, I was following them through some rolling hills in Oklahoma with a virtually identical load and they continually pulled away from me on the hills. He says he just sets the cruise and goes...

What really bothers me is that I am often passing and repassing semis going up and down the hills, since they catch me on the upswing.

I've got to the point that I'll flick off the overdrive at the bottom of every hill, and then turn it back on at the top. Not the end of the world, but a PITA nonetheless.

I took the vehicle to the dealer and complained and they did some sort of test and said there was nothing wrong. I'm thinking that the truck is just programmed this way, although I don't understand why.

Anyone out there have similar experience? Is there something out there in the aftermarket that would reprogram the thing to work differently?

 

I'm no expert, but mine was doing the same thing, ended up I needed to replace the cruise control modual under the driver side battery. If you can hold the speed with your foot the CC module must be leaking. Its vacuuum controlled.

 

Sound in the "normal" department to me, but then again, that's a hard call to make. I had similar feelings about my 01 towing the trailer in my picts. Edge EZ and injectors took care of that issue for good. Would really have to go on a ride along to get a true opinion, but I do know that the cruise on the rams will lose quite a bit of speed at times on grades before kicking down. Personally if there is enough grade I turn the od off and drive.

 

As I re-read the original post he claims he can hold speed with the cruise off. The truck is running fine then. If the truck can sustain the speed then its the cruise control not "keeping up". I'll bet there is a vacuum leak either in the vacuum system or the CC module itself.

I'm assuming the "99" CC module is operated the same as the "03". I always get in trouble trying to help other generations, but no one else is helping this guy.

 

I think you misread. I can (and the cruise control can) hold the speed with the _overdrive_ off. I don't turn off the cruise control at all, I just turn off the overdrive so the truck will gear down to climb the hill at speed. The cruise control will hold the speed up hill as long as it is in a lower gear. So I don't think a leaky cruise control is the issue, although I appreciate your effort at trying to help!

J Body may have it right, that it is normal, although as I said, my friends with the earlier truck don't seem to have a problem.

 

...of course there is the other facts left out. Does the friends trailer weigh as much? Does he have the 3.55 gears or 4.10? (your's base was 3.7 with 4.10 as an option). Oh and by the way Welcome to the board!! To tell you the truth I was a little disappointed with my 01 when I first got it, but a few little mods have made this the perfect truck for my application.

 

the cruise won't give it enough throttle to get the trans to shift out of overdrive until it drops alot. put more power in it will help though.

 

Meaning? More throttle or a power upgrade? What you say makes sense, though, as sometimes I'll jam the throttle down and it still won't drop out of overdrive.

J Body, the trailers were very close in weight, etc., but you're right, I don't know the rear end ratios.

I've looked up things like Tow Loc, which appears to give some ability to control when shifts take place, but I don't know if they will fix my problem. Probably too much money for an irritant, anyway.

Looks like I'll just have to live with it...

Thanks to everyone who responded.