tykrz

Just got a brand new 2005 chevy truck. Going down anykind of incline with the cruise control engaged this truck starts to violently buck and surge very abruptly all the way down the hill very similar to a vehicle running out of gas. This only occurs with the cruise control engaged. Took it to the dealer and they said this is normal and showed me a copy of a GM bulletin regarding this. Was told to turn off the cruise control when you go down hill. No wonder GM is in a tailspin and losing market share to the imports releasing products with driveability issues like this! I find this problem and explanation totally unacceptable as this has never happpened with previous trucks I've owned and is also a safety issue. Looks like they need to go back to the drawing board.

tykrz

PS: GM in the bulletin says no attempt should be made to try to fix this issue.

dr_of_lovephd

I have seen a similar problem before. Does your truck have an overdrive transmission? If so, try to take the trans. out of overdrive and drive for a while and see if you still have the problem.

The problem is when you are going down hill in overdrive, the truck can accelerate past the set point in the cruise control and the engine begins to engage and disengage, trying to control the speed.

If this is your problem it is not specific to gm, I have seen it in different vehicles.

tykrz

I've had numerous GM trucks and cars with the overdrive transmission and none have had this problem. I also still own a 2002 Chev SUV with the same engine and powertain and it also does not have this problem.

tykrz

ps; when this happens, it jerks so abruptly that you can hear the drive train clunking as the engine cuts violently in and out.

White Lightening

I know my 2004 Silverado doesn't do it. Lots of up and down hills in this part of the state - I'd be "cruise disengaged" half the time. I don't think I'd be any too happy with that problem if I had it

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jethro_3

Have not seen it on my new '05. Please do not share that problem with other trucks....

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awdavis01

Well, at least I don't feel special anymore. I got my truck in July and this has been driving me crazy. I drive long distances regularly and this problem really shows up during those extended periods when you have nothing better to notice. Mine is not so violent as some of you describe, but I've seen the tach bounce 200rpm at times. So that others may gather addtional symptoms, mine occurs on shallow hills as well as moderate to steep ones.

brumleveb

Mine's not so violent either, but it is there and my truck is an '04. It's a little irritating. The funny thing is that I was driving my wife's minivan (1999 Dodge) this weekend and it does the same thing. I never noticed it before on the van. I think my truck does it a little worse than the van though.

Ape0r

Real common on the NBS trucks. Doesn't seem to do it as severly as it used to in mine.. but I'm probably just using cruise less than I used to. Tach doesn't budge.

You can use the accelerator to accelerate a bit above what the cruise is set at while going downhill if you want an easy workaround. When you let off the gas, the truck will settle back to the cruise speed you have set.

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budone

My 2005 is the first vehicle I had with this issue. I have had 2003, 2002, 2001 and a 2000 and none did this.

However, my 2005 is also the first that if you want to pass someone and still keep the cruise engaged, when you apply pressure to the accelerator, the vehicle slows down. But I have become used to that.