Wah wah wah rotational hum- low frequency

[Indiana80]

Drive shaft (propeller shaft) / u-joint noise??? My 2005 LX470 emits a low frequency wah wah wah humming noise. Could be tire noise (BFG KO2s), but it starts around 20MPH and is rotational with wheel speed until it blends in with road noise at highway speed. I just change wheel bearings / races- no change in the wah wah humming noise. Have moved the tires around; no change. 217K miles on truck and prop shaft / u-joints I believe are original. I’ve greased everything. No change. Tonight I crawled under it to check for play. Front u-joint on rear shaft maybe has a very very tiny amount of play, same on rear most u-joint. If I push up and pull down on rear shaft, I get a clunk. Sounds like clunk is in center of drive shaft or just rear of slip yoke. Also can see a bit of vertical movement in the flange off the back of the t-case. I plan to replace both prop shafts with new OEM, but am wondering if vertical movement (albeit slight) is acceptable in the flange on back of t-case. Front prop shaft has slight horizontal play- maybe at the t-case or diff flange- I’ll double check both this weekend and try to post some videos. Wondering if this kind of play would lead to a rotational wah wah wah wah humming noise? Any advice appreciated!

 

[westaussielx470]

My memory is perhaps a little off but years ago I had a set of Mickey Thompson Baja AT on 200 series LC and I had a similar noise I was constantly told it was an issue with the vehicle not the tyres. I finally spat the dummy and demanded their rep drive the car and it turned out there was delamination in the sidewall of two tyres....I was given the choice of replacing them or fitting Coopers which I did and never bought Mickey Thompson again. The noise never came back. I cant stand strange noises or vibrations and have many models of BMW and I had done a full suspension rebuild of a 1996 750li which had one the best rides ever. I put new tyres on it and I had a continuous vibration that arrived with the new tyres, but the shop insisted they were fine. I took it back to the shop that did the suspension and whilst it wasn't a tyre shop, he had a really good balancer for his race gear. 2 hours later and multiple changes of valve and tyre position it was fixed.
I have learnt to assume nothing because lets face it how much does some young kid care about getting some old guys wheels balanced perfectly?

 

[newbielx470]

Does the noise change with steering wheel turned left/right?

 

[Indiana80]

Does the noise change with steering wheel turned left/right?

Nope.

 

[Indiana80]

Nope.

Wheel bearings new - I used Koyos- properly packed and installed.

 

[Indiana80]

My memory is perhaps a little off but years ago I had a set of Mickey Thompson Baja AT on 200 series LC and I had a similar noise I was constantly told it was an issue with the vehicle not the tyres. I finally spat the dummy and demanded their rep drive the car and it turned out there was delamination in the sidewall of two tyres....I was given the choice of replacing them or fitting Coopers which I did and never bought Mickey Thompson again. The noise never came back. I cant stand strange noises or vibrations and have many models of BMW and I had done a full suspension rebuild of a 1996 750li which had one the best rides ever. I put new tyres on it and I had a continuous vibration that arrived with the new tyres, but the shop insisted they were fine. I took it back to the shop that did the suspension and whilst it wasn't a tyre shop, he had a really good balancer for his race gear. 2 hours later and multiple changes of valve and tyre position it was fixed.
I have learnt to assume nothing because lets face it how much does some young kid care about getting some old guys wheels balanced perfectly?

I think I’m going to throw some new Yokohamas on it and see what happens. The BFG KO2s are 3-4 years old and maybe have 20 or 30K miles on them. I never liked KO2s anyway- other than how they look. I took a similar set of KO2s off my FZJ and put Yokohama ATs on it. Noise-wise the Yokohamas were silent compared to the old KO2s. I’ll post results late next week once Yokohamas installed.

 

[jsloden]

It's the KO2's. They're not exactly known for being the quietest tire on the planet. If you want something quiet get michelin's. They may not be as beefy looking as the KO's but they do pretty good off road and they are whisper quiet on the road. The difference in ride quality is more than enough to justify the price. They'll also last 70-80k miles given proper alignment and rotation.

 

[2001LC]

• I keep a set of Michelin tires on wheels. Just to toss on, when cashing sounds.
• Any play in spiders (AKA U-joints), and they're bad.
• Diffs or TC play, at input or output shafts, is measure with dial gauge off the flange. FSM has spec for max. Over max indicates bad bearings. Same is true for rear axle bearings.
• Condition of FDS (AKA CV) axle needle bearings & brass bushing and their grease is a consideration. I just had one I suspected, was a bad needle bearing. Went back and reviewed picture of new FDS's outer axle where it rides on needle bearing. Sure enough axle was score. Replaced the needle bearing, all good now.

Tip: Axle surface where needle bearing rides, is best indicator of condition of needle bearings. Less than 2K miles on this FDS axle.

 

[Indiana80]

• I keep a set of Michelin tires on wheels. Just to toss on, when cashing sounds.
• Any play in spiders (AKA U-joints), and they're bad.
• Diffs or TC play, at input or output shafts, is measure with dial gauge off the flange. FSM has spec for max. Over max indicates bad bearings. Same is true for rear axle bearings.
• Condition of FDS (AKA CV) axle needle bearings & brass bushing and their grease is a consideration. I just had one I suspected, was a bad needle bearing. Went back and reviewed picture of new FDS's outer axle where it rides on needle bearing. Sure enough axle was score. Replaced the needle bearing, all good now.

Tip: Axle surface where needle bearing rides, is best indicator of condition of needle bearings. Less than 2K miles on this FDS axle.
View attachment 3714382

Got it. In my case, I greased the s*** out of the spindles with Slee tool. There is probably a pound of grease behind each front knuckle. Both wheels rotate freely / no noise or rotational binding when truck is on stand and calipers off. My front wheel bearings had been run fairly loose when I bought it. First thing I did was adjust them to 14-15 ft lbs of preload. I had a dealer replace my front upper and lower control arms (SPC uppers) and shocks back in Feb. I drove the truck for a few months with some odd noises up front and truck pulled hard right at highway speeds. Finally took truck 2hrs away to a different dealer that knows LCs and they found lower control arms not torqued to spec / loose and shock mount bolts not tightened down- they were really loose. When I replaced wheel bearings last weekend, I checked upper balls joints and they weren’t torqued to spec- so I addressed that. All this being said, I suspect I introduced some uneven tire wear along the way which might be leading to my increased wuhwuhwuhwuhwuh- it’s gotten somewhat worse from when I bought it about 8 mos ago. Since my noise is starting at 25MPH, ‘bout has to be a tire, I would think. Seems ujoints or axle needle bearings would present with a vibe in the seat and / or noise much sooner than 25MPH??? I’ll post after new tires installed. Also, noise does not reduce at all when going 35-40MPH (worst noise range) and I put truck in neutral. Aside from wah wah wah that starts at 25MPH and feels like it’s originating all over the front half of the truck (maybe), the truck drives and handles amazingly smooth and tight- much better than my wife’s rather newish GX460. The noise is not a womp womp womp, but more of a wuh wuh wuh oscillating noise that correlates directly with speed- maybe like I would imagine a UFO sounds like when it takes off . If tires don’t solve, new prop shafts going in. If all that doesn’t solve, time for another 2hr drive to a competent dealer- I have no LC focused shops where I live in the land of impact guns for everything threaded and crap shoots.

 

[MountaineerLC]

I agree it could be the KO2’s. Mine were almost as loud as an MT tire. I replaced them with The Falken Wildpeak A/T4w and the difference is very noticeable. Practically no road noise with the Falken’s and I see no reason they won’t perform as well as or better than the BFG. I’ve been very satisfied with their on and off road performance.

 

[Indiana80]

Drive shaft (propeller shaft) / u-joint noise??? My 2005 LX470 emits a low frequency wah wah wah humming noise. Could be tire noise (BFG KO2s), but it starts around 20MPH and is rotational with wheel speed until it blends in with road noise at highway speed. I just change wheel bearings / races- no change in the wah wah humming noise. Have moved the tires around; no change. 217K miles on truck and prop shaft / u-joints I believe are original. I’ve greased everything. No change. Tonight I crawled under it to check for play. Front u-joint on rear shaft maybe has a very very tiny amount of play, same on rear most u-joint. If I push up and pull down on rear shaft, I get a clunk. Sounds like clunk is in center of drive shaft or just rear of slip yoke. Also can see a bit of vertical movement in the flange off the back of the t-case. I plan to replace both prop shafts with new OEM, but am wondering if vertical movement (albeit slight) is acceptable in the flange on back of t-case. Front prop shaft has slight horizontal play- maybe at the t-case or diff flange- I’ll double check both this weekend and try to post some videos. Wondering if this kind of play would lead to a rotational wah wah wah wah humming noise? Any advice appreciated!

I’m ruling out tire noise. Drove on a gravel road this weekend. Noise is the same on loose gravel- 25MPH and up- low frequency woowoowoo. Can’t detect much / if any, ujoint play when pushing vertically / horizontally on prop shafts from below. But definitely a definitive clunk when pushing up and down on rear shaft and it sounds like clunk is originating in center of prop shaft. I also notice a squeak / chirp super high frequency when driving by structures close to road, and slight rumble / vibe in floorboard. New prop shafts in order- I’m thinking. Any tips on prop shaft removal? Is there a way, with wheels on the ground, to free spin the prop shafts? Seems like it would be easier to remove prop shaft if could rotate it 180 after lower 2 nuts removed. I tried gear selector in neutral and t-case selector in neutral, still locked. My apologies for the newb driveline question. I’m learning.

 

[jsloden]

I’m ruling out tire noise. Drove on a gravel road this weekend. Noise is the same on loose gravel- 25MPH and up- low frequency woowoowoo. Can’t detect much / if any, ujoint play when pushing vertically / horizontally on prop shafts from below. But definitely a definitive clunk when pushing up and down on rear shaft and it sounds like clunk is originating in center of prop shaft. I also notice a squeak / chirp super high frequency when driving by structures close to road, and slight rumble / vibe in floorboard. New prop shafts in order- I’m thinking. Any tips on prop shaft removal? Is there a way, with wheels on the ground, to free spin the prop shafts? Seems like it would be easier to remove prop shaft if could rotate it 180 after lower 2 nuts removed. I tried gear selector in neutral and t-case selector in neutral, still locked. My apologies for the newb driveline question. I’m learning.

It's the tires. Drive shafts don't really cause noises like you're describing. And if they did you would be feeling it long before you heard anything. It's the tires.

 

[Indiana80]

It's the tires. Drive shafts don't really cause noises like you're describing. And if they did you would be feeling it long before you heard anything. It's the tires.

How how can tires make tire noise on a loose gravel road- the kind of road where you can’t go much over 40MPH without fishtailing? Anyone else ever experience this?

 

[jsloden]

When u-joints go bad in a drive shaft you will feel a vibration long before you hear anything and when you do it will be a loud clunking noise. There's no mistaking it. Axles will cause more of a clicking sound, espicially when turning. Anything in the rear end will be a constant sound and not a wu wu wu like your're describing. My 01 lx has over 450k. I've gotten pretty good at diagnosing sounds. You could always take it to a shop and and have them run it on a lift if you don't trust me. If the noise stops, it's the tires.

 

[Indiana80]

When u-joints go bad in a drive shaft you will feel a vibration long before you hear anything and when you do it will be a loud clunking noise. There's no mistaking it. Axles will cause more of a clicking sound, espicially when turning. Anything in the rear end will be a constant sound and not a wu wu wu like your're describing. My 01 lx has over 450k. I've gotten pretty good at diagnosing sounds. You could always take it to a shop and and have them run it on a lift if you don't trust me. If the noise stops, it's the tires.

I believe you…just trying to figure how loose gravel road can reveal a humming / droning noise. I’ll put it up on stands tomorrow in my garage and run it up to 25 and see if noise presents.

 

[Indiana80]

I believe you…just trying to figure how loose gravel road can reveal a humming / droning noise. I’ll put it up on stands tomorrow in my garage and run it up to 25 and see if noise presents.

Put it up on stands and ran it. I’m getting a really loud growl that’s coming from the rear wheels- hopefully not diff, but definitely could be. Ugh. Front axle rotates quietly.

 

[Indiana80]

Put it up on stands and ran it. I’m getting a really loud growl that’s coming from the rear wheels- hopefully not diff, but definitely could be. Ugh. Front axle rotates quietly.

 

[Indiana80]

Put it up on stands and ran it. I’m getting a really loud growl that’s coming from the rear wheels- hopefully not diff, but definitely could be. Ugh. Front axle rotates quietly.

 

[jsloden]

I would take the tire and wheel off. Maybe that would help you pinpoint what it is. You can definitely tell the tire is out of balance in the video though.

 

[Indiana80]

I would take the tire and wheel off. Maybe that would help you pinpoint what it is. You can definitely tell the tire is out of balance in the video though.

The verdict is in. Front diff is trash.