When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
04 cc dually 4x4 6.0 15K miles
about four weeks ago, I was at stop sign. When I accelerated, I heard a thump from underneith, kinda sounded like you have something inthe bed, and it hits the tail gate, and no, nothing was in the bed. It hasent happend again until this past friday, same thing at a stop light. I called my dealer and asked about the tranny recall, and said mine wan not one of them, and theres nothing much they can do about the noise since its so intermitent. Anyone experiece this and if so, what was the problem and remedy?/
Driving you nuts yet? It's not the tranni, it's not something rolling around in the bed of the truck........it's a trap door in the ventilation system that is vacuum operated. As you give it throttle the vacuum increases and slams the door shut/open and that is the "thump" you are hearing. If you do a search here you'll find a bunch of others that had the same problem.
'04 with 8700 miles and still thumping down the highway.
Here's another reply I just found...."Posted A Similar Thread About A Year Ago On My 04 Specifically As Rogeny And Others Describe. My Dealer Is Now Replacing The Ac Compressor And Indicated That The Compressor Is Responsible For The Vacuum Related Thump When It Engages. Dealer Is Saying That The Compressor Engagement Is Creating Too Much Vacuum. Truck Is Still Under Warranty So Was Wondering If There Is Any One Else That Has Had Their Compressor Replaced And If So Did The Thump Go Away?"
Does this thump occur only when accelerating? I have heard this thump about 3 times only when coming to a somewhat hard stop and only when the truck is not up to temp. Could this be the same 'trap door' problem? The first time I heard it really scared the tar out of me.
Rick.
05 250 V10 4x4 CC LB 4:10LS Torqueshift 3900 miles