My truck is a 2000 Chevy silverado 2500, 6L. I am having a real rough time finding out the cause of my truck bucking and shaking. It does it mostly when I have the cruise control on, the RPM's stay the same, I took it to an auto dealer and they say they hooked it up to their machine, no codes were thrown. I also took it to a friend and he said his machine shows 2 codes thrown but his machine didn't recognize the year of my truck. The closest he could go was 2001. I have had all 3 drive shafts replaced, they needed to be anyways, both front wheel bearings, they needed to be replaced too. Can anyone help me, anyone have similar problems? Thank you for your time in this.

 

it is doing it when you get to a certin speed? Or all the time?

 

Good question,l have to find out later but I believe that it only does it at higher speeds like 80 to 90 kmh. I haven't used the cruise at lower speeds but I will try. Thanks.

 

Your welcome. if its higher speeds then its a drive chain problem. double check all your u-joints and everything drive chain related.
Good luck finding out what it is.

 

Can you tell me what a drive chain is and where it is located? Also another point, when travelling down the ol' open highway it feels like it is vibrating a little bit. I just got home and used the cruise control at various speeds, the truck started shaking like it was misfiring at about 75 kilometers per hour, it even did it at 100 kilometers per hour, at 70kph it was nice and smooth, on another point when it started bucking I gave it some gas and it was alright, got back to cruise speed and most of the time it started all over again. I have lots of hills on the way to work and back home.

 

He means drive line...ie drive shaft, u joints, tranny mount, motor mounts,ect.....hows the tires? have you had them ballanced lately? front end? is it tight or worn? these ALL will cause vibration while driving.....not to mention motor issues. Also does it seem to do this in O/D or in any gear related to the speed....quick test....drive at 70 or where ever it does it at and then let off the gas and shift into neutral..........is it still there? if so then it is drive line/ front end/ tire related.....if not it is motor or tranny related......misfire could point to a tune up need or a failing coil.

 

I did change the plugs a couple of weeks ago and 2 of the 8 were fouled, I am gonna check them tonight I hope, maybe those coils need to be replaced, I honestly don't think anything is wrong with the tranny at least I hope nothing is wrong, it shifts smoothly.The tires were balanced a few days ago, didn't think about the motor or tranny mounts, also when it is idling I can feel a vibration in the steering wheel. Lots of small things eh, thanks for helping, it is appreciated.

 

When I went to work this morning I did as you said and drove at 80 to 85, let off the gas, into neutral, it was smooth, no bucking. I also had it on a fairly flat road and slightly applied the gas, it started bucking again, let it smooth out and stepped on the gas, no bucking. Not to seem like a dummy but can you tell me where the engine and tranny mounts are so I can check them. At this point I am thinking it is a coil that is failing, at least that would be an easy fix. I will check the O/D and other gears later on this afternoon after work. I still need to check the front end too.

 

ok well drive train drive line, same thing. ive always heard drive train down here.

 

On my way home I engaged the tow button, the truck only bucked once on a fairly steep hill while the cruise control was on, all these times were with the cruise control on.