I have a 2017 GMC Sierra that has a rattle when I hit 2k rpm. I cannot recreate the sound when I’m in park revving the engine, only when I’m driving. I beat around under my truck with a rubber mallet and couldn’t find the sound. I took the floor heat shield completely off and it still rattled. I’m worried it’s the catalytic converter that the original owner put on that says 7/21 (I assume the date). How can I test the cat. And what else could it be if not the cat?
thanks!
Take your mallet and tap on the converter. Also, get one of those noise finders Scotty has that are around $80. Clip the things around to find noises if it's not the cat.
Tomorrow I’m going to get a hose clamp and tie it around the cats heat shield and see if it stops the rattle.
It might be worn out drive shaft u joints as well. Check them and your shock absorber mounts to see if the rubber has disintegrated.
Do I just tap them with mallet?
https://carkiller.com/scottykilmer/qa/inspecting-driveshaft-u-joints/
the don't typically rattle though
I don't think there's an audio track. Try Youtube.
Here’s the video with sound. I deleted the other video that didn’t have sound. https://imgur.com/a/4SeI94Z
are you referring to sort of a cymbal sound about 3/4 of the way through @ 40 mph?
Yep!
well that to me sounds like classic heat shield rattle.
Do you have heat shields around the exhaust manifold and downpipe on your engine?
No I don’t. I do have a heat shield around my cat that I’m going to buy a hose clamp for today and see if it stops.