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.
Bad Vibration After New Siamese Dual Exhaust on 69 f100
Just had new Siamese style dual exhaust installed on 69 f100 2wd.. It replaced the older rotten same style/location Siamese dual exhaust it had. Looks like a good job except...after it warms up, it has a terrible vibration when it is in neutral idling. It sounds like it is coming from the bottom of the truck. I noticed the pipes are spaced nicely everywhere except where it goes over the rear end, they are touching. Could this be the source of the vibration or is it normal for this style of exhaust to have the pipes touching after a new installation ? Thanks for any advice.
And look for anywhere at all, where the tubes might be touching the frame or the body.
Even look for a peripheral things, such as the transfer case shifter getting knocked into a different gear and touching sheet metal.
That’s a long shot, but it’s not an impossible scenario.
Also, when you’re hearing/feeling the vibration, put something up against the muffler itself. Perhaps a floor Jack, or moving blanket as long as the muffler is not hot yet.
It’s not impossible for a brand new muffler to be defective.
Stuck a screwdriver in between the area where the 2 pipes are touching....the god awful loud vibration stopped. Now to take it back and hopefully the guy will re-bend the pipes so they dont touch and not stick a crow bar in there and say "ok your good" I paid 1100 for that exhaust-hopefully he makes it right. Thanks Again for Everyone's advice.
Yeah, I would hope so too.
What they did on mine was to weld a strap (or two?) holding the two mufflers rigidly together. Or I should say, rigidly apart since there was a small gap.
I took it back and the guy was super helpful. He cutoff the tail section of the pipes and re-positioned and re-welded them so they have clearance between the pipes now and are further away from the spare. He ran the pipes on top of each other this time, then had them come out side by side like before. Only thing is the one pipe sits a little lower than the spare now but it seems fine for now and no more vibration and he did it for free.
Last edited by sixty4chevrolet; May 29, 2026 at 04:56 PM.
This Hennessey Takes the Expedition Tremor's Off-Roading Capability to the Next Level
Slideshow: The VelociRaptor Expedition gains a lift, upgraded suspension, Brembo brakes, and trail-ready equipment while retaining the stock 440-horsepower EcoBoost V6.
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.
