CM870 new sound, any ideas?

[Camstyn]

Hi all, here's a bit of short history.. Truck has about 750k miles on it, 565 ISX, work that has been done is a new head (500k), rods, mains, turbo, top end inspected, crank dampener, un-mandated by a forum member here all done between 650k and 700k.

Coming home late last night the truck starts to get really loud between 1400-1600rpm. My first thought was exhaust clamp, but it sounds completely normal on the jake and at lower RPM's, just resonating loudly between 1400-1600. Also a vibration. I pulled over to check for any exhaust leaks just to be sure but can't spot any.

I then took an audio recording of the sound, you can hear it prior to shifting here, especially well starting at the 19 second mark.

Engine rattle sound

Any ideas? When free revving the truck it doesn't do it, only if it's under load. Doesn't need to be under heavy load either, it will do it at 10psi boost.

Here's a link to the audio clip.. Any guesses on what this may be? This truck has never had any injector work done.

I'm supposed to be going to Edmonton today (home in Kamloops) but hesitant to drive it like this without knowing if the problem may be serious.

Thanks!

[Hammerhead]

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I am re-PMing you my number incase you don't have it anymore.

[race7820000]

There is no link?