Desert Dually

I've been meaning to post this question here for a while, but somehow I get sidetracked and then forget all about it. Anyway, I dont use my cruise control very often, so it isnt constantly reminding me.

When the cruise control is "on", truck drives fine in all conditions except when going downhill, then it feels as if it (the cruise control) is turning on and off like once a second, almost feels like a torque converter locking and unlocking very rapidly. It makes a gawdawful shuddering that can be felt through the whole truck, like its gonna shake itself apart. Anybody else ever notice this with their truck or hear of anything like this before?

My way of dealing with it, is to slightly accelerate, till the road levels out, or just cancel the CC. It's kind of a pain in the neck, after all - cruise control shouldnt need to be "babysat" like this. I had a 1975 Chevy Monte Carlo with better CC than my truck.

Crazy Diesel

I noticed that same problem. It really sucks when we spend this kind of money on our trucks and have little nagging probs. like this. My bud who owns a diesel perf. shop said it's in the tranny. Do a vb and torq. conv. and problem goes away. Now I haven't done that yet so I don't know for sure.

MikeyB

Set the SMARTY back to stock and test again. My experience is the CC is very sensitive especially when a performance box/programmer is added. The CC over reacts due to the enhanced power. I had this same issue with the Edge EZ and with certain SMARTY programs over the years. Luckly I haven't noticed it with the Revo program.

MikeyB

DieselBoy20

Ha mine does it too, and if you think your stories are bad then get this- I was working up in Northern Alberta this last winter and I was heading to work in the morning and had a passenger with me and my cruise had the exact same symptoms you guys speak of and did it very often going down a hill. So this particular morning it was doing it a lot and I was getting pretty mad. So when I finally got real mad it was doing the shake thing and i really stomped down on the pedal and when I did this the pedal stayed on the floor and I could not get the pedal released from the floor and nothing was holding it to the floor but the CC, my floor was clean, hit the brake- did nothing, and my crap floormats definately didn't do it. While the truck was doing this I had to do something about it cuz i was doing nearly 90mph, so the only way to stop the truck was to turn the key off and thats exactly what i did and i wanna think turning a hot truck off at 27-2800 rpm can't be good for anything. Coasted the truck to the side of the road until it stopped, we both cleaned our shorts out.... then kicked the pedal that was still stuck to the floor once and it came back to its normal spot. I hardly use my cruise anymore go figure.

Foxborough

My truck has done the cruise thing too. The truck is stock not a real problem for me since it's pretty flat around here, no hills.

Roperteacher

I have a 6 speed that will do this. Not just Autos I guess. I thought it was because when you started to coast past the set MPH it has to let off, then re engage when it dropped below the set MPH??? I thought it was toally normal. Now that I have my Pac Brake it is really cool!!!! If I go to fast, the Brake engages then cthe cruise kicks back in...

'06BlueRam

I agree with Roperteacher it just coasting, diesels don't have the back pressure like gas .Thats the reason for exhaust brakes.

steelblitzkrieg

I'll have to check mine, I didn't think the pedal moved with CC in the 06 and newer because they are drive by wire vs throttle cable.

Allways_Lost

My truck did the same thing with my wife and kid in it. She was driving and I was in my work truck. She just ran off on me and I could see the smoke from the truck accelerating and her braking off and on off and on. She called me allmost in tears it scared her so bad. She also had the cruse on when she gave it a little pedal. It just took her for a ride that she wasnt prepared for.

It also surges. Has done it since I drove it off the lot. Just thought it was normal. We dont have a lot of hills here so it doesnt happen that offten.

Desert Dually

yes, my sentiments exactly.

QUOTE=My bud who owns a diesel perf. shop said it's in the tranny. Do a vb and torq. conv. and problem goes away. Now I haven't done that yet so I don't know for sure.[/QUOTE]

really? I am eventually going to do a VB and TC in my truck anyway, but obviously would like to put that off as long as possible for financial and also warranty reasons. But what I really wanna know is, what is the theory behind the VB and TC solving this problem? Especially since RoperTeacher has a 6 spd manual trans and his truck does it as well.

Ram Daddy

I can`t even use mine in North Florida , where there are even SMALL hills/inclines....

The truck will try to hold speed going uphill...so it pretty much matts the accelerator causing a downshift and LOTS of smoke , and going downhill it acts like you hit the brakes , trying to keep a steady speed ....

I just thought it was due to my 37s....I never tried using it before it was lifted.

GTX

My 07 and old 04.5 do it. I figured it was the cruise trying to keep the speed where you set it.

Anybody have your cruise just turn off for no reason? My 07 has done that 2 times. Not fun when the semi behind you all sudden runs up on you.
Dealer has no idea. Going back friday, will have to ask again.

Sapps

Same here, edit me off to no end. Especially since I run 100K miles a year.

Stock yes
smarty yes
stock trans yes
built trans yes

madhat

Mine surges going up hill... never had it going down...

spuddnut

My 06 stock mega cab 2500 CC goes on and off for no reason I do not have any surge problems as I am pulling a load and Jake holds well going down hill with CC on only gains about 5mph and we have mountains in Az. and New Mex. where I travel