High Speed metalic noise & vibration

midwestdave33 · December 1, 2015

I have a 2014 6.2L LTZ Wheelchair Accessible Silverado built by SVM Mobiltiy and I'm having a VERY loud metallic "clanking" or "vibrating" NOISE when I hit the speed limiter in my truck at ~100mph.

The truck is still pulling hard @ 100mph and the onset of the noise is NOT gradual its sudden and immediate and very audible.

Does anyone else have this issue?

At first I thought driveshaft vibration or a warning noise from GM when speed limiter was reached...

PRE-EMPTIVE STRIKE:

-Yes, I do this on private roads

-Yes, the dealer has inspected both road force and the driveshaft and have found no issues.

-Yes, I'm in a chair from a car accident.

-YES, I have safety equipment including a 5 point harness.

-NO, I was not driving, my father was. and no we weren't speeding, it was caused by a blowout.

-NO, that did not take away my love of racing.

-YES, I HAVE SPEED RATED TIRES

ok, I think that covers the pertinent details....

txmuder · December 4, 2015

So did you ever figure out what was causing the vibration ? I have vibration at 100 mph then it stops at 106-107 mph and runs as smooth as glass. My 2012 did same when I had the gears changed from 3.42's to 4.10's except it was vibrating at 90 mph and stopped at like 92 mph. I had same company do the gear change on this truck, originally when I asked them about the vibration I was told it has something to do with how the truck's drive shaft reacts with change in ratio (I want to call BS on that) which did not really make since to me but I just lived with it. But I am going to check further into it this time to be 100% sure.

Jim

fondupot · December 4, 2015

Can you get a video of the sound?

midwestdave33 · December 6, 2015

i wish i could, i want to get a go-pro camera and set it up under the truck to see the drive shaft and how much it deflects. if that's not it hopefully capture the sound and go from there but no i havent figured it out yet and i'm not brave enough to push it past the noise to see if it stops... if you've seen my other posts in the pictures thread i'm already a quadreplegic from a car accident involving a bad tire so i err on the side of caution.

txmuder · January 13, 2016

OK so back on this subject......Monday I took my truck to a drive train specialist here in Houston and they removed and ran a balancing test on my drive shaft up 3K rpm and it tested perfect. So seems that eliminates that as one of the problems, so when I was leaving the shop and getting onto the freeway I ran it up to 100 mph+ and the vibration was almost if not all gone for some reason ?

Now I did just change wheels and tires last week and they might be a little off on balancing as I do have a slight vibration still but nothing as it was. So I will take it in to have tires re-balanced to be sure.