Odd sound coming from Chevy Express @ highway speeds?

[Slapmackie]

I have a 2007 Chevy Express AWD w/ 40k miles that is putting out a pretty odd sound around 70 mph, kind of sounds like rumbling bass and I can feel a very mild vibration as well. It get's pretty loud and I'm worried it might be something serious. I've been told by multiple people that it's just an anomaly, typical sound from driving an empty van that hasn't been insulated as of yet. From 0-65 mph and over 75 mph it purrs like a cat! I just installed new wheels and tires and replaced a bad tie-rod end and it's still there. The van was purchased from north Ohio so it has it's fair share of rust on the undercarriage. Has anyone else experienced this and if so, did it go away once the interior of the van was finished out, or was it something mechanical? Thanks Guys...

 

[Buddha.]

Wheel bearings come to mind. If ypu can make the sond louder or quieter by steering left/right at speed that be my guess. Also you could make sure youve got fluid in the rear diff. Then there's the carrier bearing, not sure what they sound like when they go.

A bad bearing will typically make a low pitched growling kind of sound.

 

[Johny5]

Bad ujoint ?

 

[Kyron]

does the sound go away/ change if you take your foot off the gas?

* also check that there's nothing lose on the exterior, .... that can make for some weird noise

 

[Slapmackie]

does the sound go away/ change if you take your foot off the gas?

* also check that there's nothing lose on the exterior, .... that can make for some weird noise

No, the noise just stays the same no matter if I'm on the gas or not. As long as it's rolling at 70mph it's doing it...

 

[Kyron]

most likely not the differential then

 

[86cj]

The roof on these vans can make some weird noises and vibes, booming Etc...

I put a crossbar on my roof with no fairing and at certain speeds and wind conditions it did some weird stuff, almost spooky to your senses and that was with a headliner. GM has had an issue with the high strength steel roofs of some new trucks and SUV's (maybee vans too)? they might not have the right amount of flexible adhesive bonding the roof to the crossbows and causing similar issues. You very well could have a mechanical issue, look on the bright side it should get worse if you do and that will make it easier to find......

I have put a beach towel and floormat on my roof to help the ringing sound while trying to sleep during an all night rain, good excuse for a fiberglass raised roof?

 

[Slapmackie]

The roof on these vans can make some weird noises and vibes, booming Etc...

I put a crossbar on my roof with no fairing and at certain speeds and wind conditions it did some weird stuff, almost spooky to your senses and that was with a headliner. GM has had an issue with the high strength steel roofs of some new trucks and SUV's (maybee vans too)? they might not have the right amount of flexible adhesive bonding the roof to the crossbows and causing similar issues. You very well could have a mechanical issue, look on the bright side it should get worse if you do and that will make it easier to find......

I have put a beach towel and floormat on my roof to help the ringing sound while trying to sleep during an all night rain, good excuse for a fiberglass raised roof?

Yeah, I have crossbars as well but it made this sound when I first picked up the van and the roof was bare. I'll be installing my solar panels and fan soon so I hope to have it insulated soon after. If that doesn't take care of it I guess I'll start checking bearing Etc...

 

[45Kevin]

Go out and buy a 6" wide roll of butyl roofing membrane. Blueskin is one brand.
It is peel and stick. Stick some pieces on any large exposed panels, like the roof.
It would be a relatively inexpensive test.

Another theory, have been wheeling lately and rubbed/knocked the weights off/bent the drive shaft?

 

[Slapmackie]

Go out and buy a 6" wide roll of butyl roofing membrane. Blueskin is one brand.
It is peel and stick. Stick some pieces on any large exposed panels, like the roof.
It would be a relatively inexpensive test.

Another theory, have been wheeling lately and rubbed/knocked the weights off/bent the drive shaft?

I just purchased all the insulation for it yesterday so I'll soon be taking care of that. If it still roars I'll just have to move on to other options. Not exactly sure by what you meant in your last comment? "Another theory, have been wheeling lately and rubbed/knocked the weights off/bent the drive shaft?"

 

[86scotty]

Sometimes drive shafts are weighted in places like wheels to balance them.

My vote is for tranny/transfer case fluid needing to be changed. AWD Chevy vans are very particular about this. If you have never done it I would do that first.

 

[Slapmackie]

Sometimes drive shafts are weighted in places like wheels to balance them.

My vote is for tranny/transfer case fluid needing to be changed. AWD Chevy vans are very particular about this. If you have never done it I would do that first.

Ahhh, wasn't aware of the DS needing balancing!? I'll get my fluids changed first and see if that remedies it! Thanks Scotty!