Annoying sound since putting on new tires (I'm stumped)

[landscrambler]

Okay, I've seriously searched every thread I can and can not find anything that matches what I'm dealing with. (Also, pro tip - when searching on google, add site:forum.ih8mud.com to the end of your search)

Anyway, since I put 33s on my 62, I get this strange repetitive hum noise. It increases with speed, sounds like tires revolving. I've put in neutral while at speed and it still makes the noise. It sounds like it's coming from the rear but I'm not 100% on that. I can't visibly see anything touching the tires in the wheel well. I'm open to trying other ways to isolate it, if anyone has any ideas.

Lastly, when adding weight in the rear (like three people in the back seat) or filling up gas, it appears to be louder.

Please lord, send me an angel. Thanks

 

[NMC_EXP]

Could it simply be normal noise made by that specific tread pattern?

Tire pressure and/or gross weight can affect tire noise.

 

[landscrambler]

Possibly but it would seem like the sound would me more consistent, like a constant hum. This is more like

(as I'm accelerating)
hum
humhum
humhumhum
humhumhumhum
humhumhumhumhum

 

[NMC_EXP]

Could be the tires are causing a resonance in the bodywork/sheet metal. Resonant conditions often get into a cyclic pattern that builds up.

 

[micruz60]

Rear pinion?
How many miles on axles since service, if known?

 

[Spike Strip]

Seems to me like you got a hummmmer .....

 

[SteveH]

Mud tire? What brand/style of tire? What pressure are you running?

Try running them at 20 psi, and then 50 psi, and see what difference that makes.

 

[landscrambler]

@micruz60 unknown - I've read quite a bit about bearings or ujoints, not sure where to begin here though

@SteveH 33x10.5x15 BFG ATs T/A K02 - running 38psi on all 4 currently

 

[SteveH]

That should be a very quiet tire. I doubt it's the source of your noise. 38 psi seems like a bunch of pressure!- might do a chalk test and see what's best for the weight of your truck.

Louder with weight in the rear - how about a rear wheel bearing? I would elevate the rear of the truck (the entire axle) and carefully run the truck in gear and listen to the outer wheel bearings with a mechanics stethoscope. This is inherently dangerous, so block up the truck well and have a helper nearby to listen/help/keep an eye on things. Any shop with a lift could also safely help you with this. I had a similar noise in my '98 4Runner and it was incredibly obvious on a lift (with no load on the axle). I did not need a stethoscope to hear it!

 

[roadstr6]

I run my 33x10.5 BFG's at 28 lbs. A worn transfer case can make a lot of noise too. Those seem to make more of a howling noise when your are on / off the gas kind of like riding in an old school bus.

 

[MANUCHAO]

As stated check your rear pinion for any play.
On a flat area block all wheels, disengage the parking brake with the rig on neutral, and check for up / down play, any leaks on the pinion area. Check the DS joints as well.

 

[FishTown]

Let's see/hear a recording of the sound. Doesn't sound like normal tire noise to me.

 

[gregnash]

Like some of the others are saying.. it sounds like it is a drivetrain issue not tires. Since you just recently went to newer, bigger tires they are probably putting added stress on the drivelines and other items and thus making noise.

I would start with things like the u-joints at the drive shafts and grease them to see if anything goes away. Also check the fluid levels in your diffs AND t-case/tranny to ensure they aren't dry. Once that is all done then I would go about checking axle bearings and whatnot.

 

[landscrambler]

I just posted a note on Nextdoor to see if anyone in my town is willing to share their garage. I live on a hill and have a small garage and not many tools currently.

I'll try to get a recording of the sound today but it's pretty subtle.

@gregnash any particular type of grease for u-joints / driveshaft?

 

[landscrambler]

If it is a drive train issue, would the sound be repeating as if it's a tire rotation? Some of the videos I've watched on drivetrain issues, the sound is constant, like a continual hum.

 

[gregnash]

Could be a repeating sound. For grease/lube... diffs and tranny/t-case take 80w90 gear oil. For greasing the u-joints that is probably going to be a good quality bearing grease.

 

[landscrambler]

Okay, you can kind of hear the sound towards the end of the video. Crank up your volume Also, taking to a shop that has a lift on Wednesday. Going to try @SteveH 's advice to drive while up in the air.

 

[roscoFJ73]

It sounds like a bearing to me, diff maybe

 

[gregnash]

Yeah that is what I was thinking I was hearing.. Check your rear diff fluid level and grease the u-joints. If it persists then may be time to pull the rear apart.

 

[landscrambler]

Is the rear diff fluid valve on the backside of the diff? about half way up