Rhythmic hum a la "Living on a Prayer" - Possible Rear Wheel Bearing
 

After 100 miles round-trip on washboarded Hole in the Rock Road Road in UT, I started hearing a rhythmic hum a la background vocals on "Living on a Prayer" - LOL!

Goes "woo-woo-wah-woo-woo--wah"... :banger:
Sounds more rubbery (like running on flat tire) than metallic. Mechanic brother-in-law (test drove it) says it does not sound or feel like the drive-train so I had tires balanced and rotated but I still hear the hum.
It's faint over road, wind noise, and the purr of the 22RE (spoken in the tone of the Dos Equis Man).
Happens in low and high speeds (speed dependent).
Happens in gear or in neutral.

Truck also (intermittently) started to buck/hesitate when I'm try to accelerate when gear is too low for the speed. Could be related (clutch slipping) or separate issue from bad fuel from the backroads of Utah? I already used STP fuel injector cleaner and refilled with two tanks full of name-brand gas.

Please comment if my plan to isolate source or hum is sound (no pun intended - LOL):

• Chock 2 front wheels and one rear wheel, jack up remaining rear wheel off the ground.
• Tie cord to throttle cable so I can pull and rev up remotely (keep cord away from moving part, or course)
• Observe drive shaft as it runs.
• Probe suspect areas (transfer case, brake backing plate, what else?) with long wooden rod held against ear so I would not be under the truck :)
• Do the other rear wheel.
• Jack up and spin wheels manually to feel for bad bearings. Rear wheels may be hard to check that way?
• Inspect brakes

[b]Brainstorm - Any other ideas?

keywords: Rhythmichum, rearwheelbearing

It sounds like your truck is down on its luck
It’s tough, sooo tough
Well, you need our help so we’ll give it a shot
Since you’ve described it for us,
We’re half way there
we’re beyond just, livin' on a prayer
Take these guy’s advise, you'll make it I swear

:banger:

In either of those conditions does the sound change in either volume or rhythm?

jack up the whole rear and let the truck idle, should show you which side but do both anyway

Thanks, guys!

Yeah hoping it's just that or other parts that are less expensive to replace.

LOL! Yup! :)

Yes, frequency increases with speed.

Sure, will try that.

Not enough Coffee yet !

I am sure any fluid loss would have been mentioned !

I dated a women long ago that drove a Car that the differential screamed you could hear her coming a mile away never leaked .

Does this have a Center bearing I always called them Carrier bearings That would be my first suspect .

Every rear wheel bearing I had that started to fail started leaking not that it might not leak

Then to me I can feel them by spinning the wheel

Bearing tend to make a grinding rough noise and get hot and start leaking .

All good suggestions. I'd add u-joints to the list of potential suspects, which you can isolate by driving in 4wd with the rear d-shaft disconnected.

Rear Wheel Bearing It IS!
 

Thanks, guys! I'm pretty confident, and am glad it is just the rear-wheel bearing and not the drive-train.

https://lh3.googleusercontent.com/u6...=w1380-h776-no
JACKED UP REAR

McGyverism, Dude! LOL!
https://lh3.googleusercontent.com/_W...=w1380-h776-no

https://lh3.googleusercontent.com/i2...=w1380-h776-no

I probed transmission, transfer case, and differential with wooden rod and did not hear it.
Then I listened to and felt the rear-bearings. Right-rear bearing sounded louder and feels gritty. I think that's it. Next is to see my Factory Service Manual and search Youtube for R&R procedure.
Inputs / recommendations / tips on Remove and Replace procedure would be appreciated.

Thanks, Wallytoo!
Yes, Alexman says "OEM Koyo bearings from Marlin Crawler". (https://www.marlincrawler.com/search/node/MCAX-241)

And Alexman to the rescue once more! :)

Yeah, the shop press would surely help. As Alexman suggests, I'll take the axles out and find a shop to press the axle out and bearings back in.

Glad your doing both !!

In Sunny California things should come apart easy compared to here .

A slide hammer works great to pop the axles out .

Good luck

So it's true . . . you can hear things if you put a wooden stick to your rear end. But did you hear the ocean or Bon Jovi? :)

Parts needed
 

Thanks, guys!
This is al I'm gonna need, correct?
https://www.marlincrawler.com/axle/r...ce-kit-1979-99
https://lh3.googleusercontent.com/wX...W=w640-h480-no


Yes, researching most feasible way of doing it.

I got the idea from another member here... Maybe C0_94_PU?
I wish I could hear this ocean... :)

How Critical Is Re-installing Bearing?
 

At 15:51 mark on video, Alexman merely taps the bearing in.
A machine shop I checked with says it has to be pressed in a certain distance / pressure. How critical it that really?
Machine shop quotes NOT TO EXCEED $75 per side to press out and re-install. Sounds fair? Considering that dealer would charge $1400 parts and labor, that sounds good to me.

What does the FSM say about the bearing install?
and
That beach life AM wake up must reeely suck.

As long as the bearing and collar are on the axle so that the snap ring may be installed, that's all there is. No other force need be applied.

FSM: Rear Axle, Replace Rear Wheel Bearing, etc
 

Thanks, Millball. Yeah, that's what I gather from Alexman's video. The FSM (below) does not mention any specs, either; just tap it in with the SST...

https://lh3.googleusercontent.com/fc...=w1305-h759-no

https://lh3.googleusercontent.com/u6...=w1366-h753-no

https://lh3.googleusercontent.com/VU...t=w934-h263-no

https://lh3.googleusercontent.com/30...R=w885-h759-no

https://lh3.googleusercontent.com/h4...=w1137-h634-no

https://lh3.googleusercontent.com/-k...=w1286-h751-no

https://lh3.googleusercontent.com/Va...=w1176-h759-no

Hey guys, AlexMan here. Just a bit of added info about the rear wheel bearing, and bearings in general. YouTube is a pretty big stage and people get all hot-headed behind a keyboard. I'm pretty used to being told I'm wrong and a moron. Sometimes they are right, but let me clear up a common misconception. Many people have heard it's bad to hammer on bearings and you will immediately destroy them. It's 100% okay to hammer a bearing in or out as long as you are hitting the race that is stuck. If you are installing a bearing into a hole and you hammer on the inner race, then all the force is transmitted through the balls. This IS bad. Same goes the other way, if you are installing a bearing onto a shaft, then you want to hit the inner race. If you hammered on the outer race then you would be transmitting force through the balls. So as you can see in my video when installing the wheel bearings onto the axle, I use the angle iron to tap the bearing on. The rear wheel bearings are a slip fit into the bearing pockets but a press fit onto the axle shaft. Now, when using a press, you can press on either race to an extent. You won't be applying any shock loads with a press. The shock loads are what are bad for the bearing balls. But with a press you do have the ability to quickly overload a bearing to the point of damaging it. So with a good mechanic's feel, you can press either race as long as you have a good feel for when to stop to prevent overloading the bearing. Still a good idea to press on the race that is stuck but in certain situations you may not have that option.

Some more info. My press was $99 from Harbor Freight. I've gotten a lot more use out of it than I expected. Well worth it if a shop is quoting you $75 per side. Also, no specific depths for the bearings. Press them til they stop or when the sound of hitting them with the hammer changes.