Highway speed low-pitch rumble

[NJRadioGuy]

2022 JLUR here. For the last several months I've been getting a deep, low pitched rumble that's speed-dependent, but not engine RPM-dependent. Flat ground, uphill, downhill, in gear, in neutral, doesn't matter. It starts around 52 MPH and gets louder as speed increases. To be clear, it is NEVER present at typical local-road speeds of 40-45 MPH, and just a hint at 50.

When it first starts out it's not constant. It almost sounds like something at relatively low RPM is at cause. Best way to describe it is by imitating the sound. rrrRRRRRRRRRRRrrrrrr over a few seconds, repeating. Then it becomes constant as speed increases and is steady by 55 MPH. After 60 MPH it is incredibly loud, but decreases slightly approaching 70. I don't drive over about 72 or 73 for fear of something grenading as a result.

The entire driveline has been inspected from front to back by a highly-respected Jeep shop in NJ, differentials drained and inspected, and they even replaced the 4.88 gears with a brand new set (that second 500 mile break-in sucked), but nothing's changed. I have a feeling that there is something very very wrong and I'm afraid of taking any kind of long highway drive in it, but to date, nobody's been able to diagnose it.

Any starting points that I could point a different shop towards, or something maybe out of the ordinary? Could this be a potential transfer case failure in the making? Axle or driveshaft failure waiting to happen? Bad CV (mine didn't have the usual U-joints)? I'm completely stumped and have no idea what I should do next, and it's driving me crazy.

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[azwjowner]

Every time there's a weird noise, I post a link to these: https://steelmantools.com/products/...q2vBcM1K8bNaMHLJaLkQY2xEAXKk1Eom3uBu-YC0EiWts

Why guess when you can narrow it down?

Otherwise, I'd start by removing the rear driveshaft and driving in 4H, see if it still occurs. It It's very likely somewhere downstream of the transmission. Wheels, axles, etc.

 

[NJRadioGuy]

Every time there's a weird noise, I post a link to these: https://steelmantools.com/products/...q2vBcM1K8bNaMHLJaLkQY2xEAXKk1Eom3uBu-YC0EiWts

Why guess when you can narrow it down?

Otherwise, I'd start by removing the rear driveshaft and driving in 4H, see if it still occurs. It It's very likely somewhere downstream of the transmission. Wheels, axles, etc.

Interesting device. Might be worth a try. Definitely not wheels/tires (swapped both out and no change).

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