1. Welcome to PlowSite. Notice a fresh look and new features? It’s now easier to share photos and videos, find popular topics fast, and enjoy expanded user profiles. If you have any questions, click HELP at the top or bottom of any page, or send an email to help@plowsite.com. We welcome your feedback.

    Dismiss Notice

Drivetrain noise

Discussion in 'Chevy Trucks' started by NCat496, Aug 20, 2009.

  1. NCat496

    NCat496 Senior Member
    Messages: 353

    I have 2 2007 Classic 2500HD 8.1/Allison and they both make a clunking noise when you hit the gas from a stop. they do it with plows on or trailers but not empty. I have been to the dealer many times and they keep telling me that the motor is too big for the truck, well the factory installed it. I dont know what to do anymore, has anyone else expierenced this problem? They are both still under warranty.
     
  2. 2COR517

    2COR517 PlowSite Fanatic
    Messages: 7,115

    Wow. That is absolutely unbelievable. I would be on the phone with the regional GM guy today.
     
  3. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Thats one of the best ones I've heard in a while. Just a nice way of passing blame because they can't or don't want to fix it.

    Need more details on this clunking sound. Is it just a single clunk when the truck is torqued up? Or it continues? Any ballpark area it seems to be stemming from? Mileage?

    Being 8.1 equipped I'd first be checking the motor mount on the driver side of both trucks as the 8.1's will break one from time to time, thus allowing the engine and trans to move upward under torque.

    These trucks has a couple other minor issues that dealt with clunking noises (body bushings and drive shaft slip yokes) that could be heard or felt by the driver but they had them pretty well covered by the '07 model year.
     
  4. NCat496

    NCat496 Senior Member
    Messages: 353

    It is a double clunk when the truck is torqued up, sounds like it comes from the front when a plow is on it. It comes from the back with a trailer, then sounds like the clunk goes to the front. Someone else told me about the motor mounts but the dealer told me they were fine. My truck has 57,000 on it and my dads has 32,000 on it. But both have the same problem. We also dont abuse our trucks we use them, so abuse is not a factor.
     
  5. NCat496

    NCat496 Senior Member
    Messages: 353

    Also I forgot, it is continuous with plowing because it is stop and go but once it makes the noise it doesnt happen again until the truck comes to a complete stop.
     
  6. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Since it's related to the suspensions height and changing directions has a consistent effect on it I'd be going over the various suspension pivot points checking for anything loose, shock bolts (and shocks themselves), sway bar attachments, cab mount bolts, and cross member bolts. Not a quick answer fix, just need to start somewhere in an attempt to narrow it down. Likely the same reason they can't or won't fix it. They don't get paid well for this type of diagnostic time so unfortunatly they want little to do with it.