HEllo all,

I have a 2015 chevrolet express 2500 van. the van does have 160k miles and did a lot of sitting the past two years. I have noticed this clicking noise. It is a sort of clackity clickity noise if that makes any sense. It sounds like a marble is rolling around somewhere inside SOMETHING. It sounds like CLICK CLICK CLICK in a RHYTHMIC ORDER. It increases with the rpms of the engine. When it increases it starts sounding like a small marble is bouncing around inside somwhere. so then it becomes more of a RATTLE noise. IT is faint, and hard to hear if someone is talking or listening to music while driving. at start up the noise is loudest (rpms high there without having a foot on the accelerator)and that is when I rush underneath the vehicle on the creeper (aka LAND YACHT) to find the noise. So far I haven't had any luck. It seems to be coming from underneath the vehicle but no idea if it reverberating off the dog house and engine and coming down. I am not sure if it is coming from the pulleys, the engine, tranmission, or cat. THE NOISE DOES also increase WITH RPM and driving around I can hear that rattling noise and it gets LOUDER like a marble rolling around inside something. I am not sure if this noise was there before I switched out my fuel pump. the old one the top of the pump, the plastic part with all the electronics and fuel lines the main fuel line had become brittle from heat. I switched out the pump and getting 1 mpg better gas mileage because that was leaking tons of my vapors off. I think the reason behind the brittle fuel pump line on the pump was someone running the tank low on fuel on 110 degree day. So perhaps this noise is ok and just the new pump working well with the engine? OR Could this vehicle perhaps have a really severe fuel problem somehow causing a lot of heat in the system, and thereby destroying fuel pumps? I get 13.5 mpg on average. not sure if that's good mpg or not. here is what I checked so far.

I checked the flex plate and the bell housing through the little inspections covers. no cracks
I looked at my pulleys and fan. My BRAND NEW water pump pulley is wobbling like crazy along with the harmonic balancer. My fan spins true enough.
Checked the cat and put my hands on it while running to see if that would quiet it. dId not
checked the exhaust manifolds, bolts are rusty but holding, not the problem.
Checked oil and it's level seems to be where I left it. My oil is kind of hard to see against the dip stick though. really wish they could make it easier to read dipsticks. smells good looks good
checked tranmission oil. good pink color and smells fresh just like the day I bought it.
checked codes and nothing stored or pending.

I am stumped here. THis is a video. the first part is me starting it, and the second part is the clicking noise after it's been running a couple minutes. The other thing to is that I SOMETIMES have a rough shift from 1st to 2nd. IT usually only happens right when the vehicle is getting warmed up, but sometimes it happens randomly say for instance after getting a green light after stopping at an intersection and moving forward. kind of feels like the engine is stalling for a second or just a jerky shift is really what it feels like. A jerky shift. Is there any way I could've butchered and messed up the install of the fuel pump and or water pump thereby creating this noise? I also did hit a massive flood zone a few months ago, but was able to get out without the tires going past the mid point i do believe. I hit a giant 1.5 foot deep water puddle at 45 mph and went hydro planing. the front splash guard broke but I don't know if that was PO or not. Don't know if a branch went up through the pulleys but I don't see any signs of damage to the belt like I'd expect. perhaps its more than one thing breaking at the same time? the van does have 160k miles and did a lot of sitting the past two years.

Other than the noise, the weird shifts SOMETIMES, and the water pump and HB pulleys wobbling LIKE crazy, it runs real good. Should I be concerned and do you have any ideas of things to check?

Let me know. DOES YOURS MAKE THIS NOISE?

https://odysee.com/@MarksChannel:7/weirdCLICKINGnoise:b