High pitched harmonic whine on highway

[scoobycarolanNC]

Hey y’all. I just lifted my gladiator with the EVO Elements 2.5” kit with front control arm brackets and shock spacers. I have Mickey Thompson Baja boss M/Ts in 37” that I’ve already been running for 8K miles. I never heard this sound before….

I’m on the highway at like 70-80. I start to notice on certain pieces of pavement & im the wheel is turned slightly right there is a droning high pitched harmonic sound coming from the rear end. Definitely not always there. Seems to happen only on certain types of asphalt like where the road is resurfaced. No grinding or vibrations. Tires feel balanced. I did have to pull the brakes and replaced the brake lines to install the kit. Maybe it’s something in the dust shield maybe a bearing is going bad?

I’m on a road trip 300 miles from home. Any ideas are appreciated.

Sponsored

 

[Rusty PW]

Changes in the pavement will cause the tires to change their pitch. Plus changes in tread depth too. You should hear how Michelin Cup tires are like on my Nismo.

 

[WILDHOBO]

Hey y’all. I just lifted my gladiator with the EVO Elements 2.5” kit with front control arm brackets and shock spacers. I have Mickey Thompson Baja boss M/Ts in 37” that I’ve already been running for 8K miles. I never heard this sound before….

I’m on the highway at like 70-80. I start to notice on certain pieces of pavement & im the wheel is turned slightly right there is a droning high pitched harmonic sound coming from the rear end. Definitely not always there. Seems to happen only on certain types of asphalt like where the road is resurfaced. No grinding or vibrations. Tires feel balanced. I did have to pull the brakes and replaced the brake lines to install the kit. Maybe it’s something in the dust shield maybe a bearing is going bad?

I’m on a road trip 300 miles from home. Any ideas are appreciated.

Mine does it as well sometimes. Identical to your description. High speeds, but only certain roads. I think @Rusty PW is likely spot on. I have no mechanical issues either that I’m aware of, or have discovered. I have the same tires you do as well. I’m experimenting with lower pressures starting today actually. I’ll see this weekend if it continues.

 

[scoobycarolanNC]

Wow. I’ve never experienced this and we’re high up in the mountains now & temps dropped so my psi is WAY down. I’ll boost em and report back after the trip home. Thanks!!

 

[Ted Striker]

I have a whining noise from the rear end of my Gladiator. It's noticeable at highway speeds but really noticeable between 40 mph and 50 mph. So far, I've been through 3 sets of Yukon 5.13 ring and pinions and now it is in the shop to get the rear outer pinion bearing replaced for the 4th time. Needless to say, this has been going on for 8 months and still can't figure it out and I'm about at my wits end with it and ready to dump the whole thing.

 

[WILDHOBO]

I have a whining noise from the rear end of my Gladiator. It's noticeable at highway speeds but really noticeable between 40 mph and 50 mph. So far, I've been through 3 sets of Yukon 5.13 ring and pinions and now it is in the shop to get the rear outer pinion bearing replaced for the 4th time. Needless to say, this has been going on for 8 months and still can't figure it out and I'm about at my wits end with it and ready to dump the whole thing.

Mine definitely isn’t gears. It’s either a tire tread wind noise or maybe wind getting into an LCA skid at high speeds. After all the mods, putting mine in a wind tunnel would be like being at a comedy show.

 

[scoobycarolanNC]

Well mine was the tires for sure. Went from 26 to 31 psi and the sound disappeared. Thanks @Summitdan

 

[scoobycarolanNC]

Well mine was the tires for sure. Went from 26 to 31 psi and the sound disappeared. Thanks @Summitdan

I also averaged 3mpg better!

 

[WILDHOBO]

I also averaged 3mpg better!

I called Mickey Thomson and they told me I was running too high. They asked specific questions regarding the original tires and psi spec. Based on that they said to run 27psi. It sounded crazy low, but it worked and it drove great. I’m assuming my mpg is now lower, but it rides better.

 

[scoobycarolanNC]

I called Mickey Thomson and they told me I was running too high. They asked specific questions regarding the original tires and psi spec. Based on that they said to run 27psi. It sounded crazy low, but it worked and it drove great. I’m assuming my mpg is now lower, but it rides better.

That's what I thought too originally, but the factory tires are a D class and the Baja Boss M/Ts are a C class. Totally different load ratings so totally different psi. The recent cold snap had me drop from 28 to 24 and I hadn't noticed. Now I'm hovering around 29psi cold which is a pretty good spot.

 

[WILDHOBO]

Mines the opposite. The original LT285/70R17C’s were C rated and called for 37psi. The 37x12.5xR17LT’s are D rated. Mickey Thompson tech support is who told me to run 27psi cold, which makes sense to me.

 

[pbrevo64]

Interesting. I put on 35x12.5r17 Baja Boss AT a couple months back, and also noticed a new faint hum, mostly on the highway. Not when accelerating or decelerating, but only when at a constant speed, usually on flat ground. Running 32psi cold, might try dropping it a little bit to see if it disappears, but good to know it isn't just me. Interesting to hear it is the MT as well.

 

[Rusty PW]

You guys should hear what a set of worn out 38" Gumbo Mudders sound like. Put you to sleep in about 45 minutes.

 

[22EcoDs]

on my Nismo.

You just flex this on every post you can yet you won't accept another son. Wtf.

OP: step 1 check the passenger seat. Step 2 if you have a go pro, strap it to the passenger side and then driver's side and see if you can hear it louder. Could be a wheel bearing if it only happens on certain load.

 

[Rusty PW]

You just flex this on every post you can yet you won't accept another son. Wtf.

OP: step 1 check the passenger seat. Step 2 if you have a go pro, strap it to the passenger side and then driver's side and see if you can hear it louder. Could be a wheel bearing if it only happens on certain load.

Sorry.

I used the Nismo as an example. Because it's sensitive to changes in pavement surfaces.

OP found his problem by changing air pressure. Post 7.

Sponsored