Vibration/sound coming from rear tires/wheels

[Hahn007]

I have an annoying vibration/sound that I believe is coming from the rear axle tires/wheels. 

[Rickf1985]

Are you sure you don't have a bad U-joint? out of balance wheels usually don't make any sound.

[TerryH]

Are you sure you don't have a bad U-joint? out of balance wheels usually don't make any sound.

Agree. sounds like U-joint.

[Rickf1985]

A hum/fast vibration could be a U-joint or a center support bearing.

[M & J]

You need to define the noise. Thump thump could be a knot or flat spot on a tire also causing a vibration. If its a squeek squeek it could be a U joint going out.

[GONMAD]

Also look for problems with the center support as they are prone to failure. I think they are underengineered for the job C YA! GONMAD

[Froggy1936]

Easiest way is to replace all 3 U joints and the center bearing . That eliminates the drive shaft  Check pinion nut for tightness wile it is exposed also check all  lug nuts  !  Frank

[Hahn007]

Thank you for all of the replies so far.
I thought about u joints as well but wasn't really sure how to determine when they are worn out unless they are extremely worn to the point that they clunk when trans is shifted into gear.
I replaced the center bearing about two years ago.
The noise/vibration is definitely more of a hum sound and is definitely road speed related. Doesn't do it in second gear at same rpm as in third....

[LJ-TJ]

Something you might look into is, are your tires steel belted radials? If so you may have one or the belts seperating. Lauren and I had a similar situation like that and for some strange reason I took the rig to a tire shop in Dunkurk Ohio. As soon as they put it up on the host you could see a slit buldge in the tire. Replaced it and every thing was tickity boo. Not saying that's your problem but may be worth checking out. If you get a clunk when you put the rig in gear...forward, nutural and reverse. It may be the universals. As so if when your driving down the highway and look in the rear view mirror and it's viberating it may be the u-joints. Sorry mate but that's my best guess. Hm?

[Froggy1936]

Tickity Boo , TJ Your a hoot  :)rotflmao! Frank

[M & J]

Beat me to it Frank. Tickity boo indeed

[Hahn007]

Will try to describe sound......

RRRrrrrrrr......RRRrrrrrr.......RRRrrrrrr

Bad at about 55 mph and around 60 mph.
Nice and smooth at 50 mph and 65 mph.

Feel the vibration mostly in the floor and the seat bottom.
Can't feel hardly any vibration in steering wheel.

[Rickf1985]

Are you sure you do not have a bad motor nount or a part of the exhaust system touching the body somewhere. OR, an exhaust hanger without a rubber isolator.

[Piraterik]

Are you sure you do not have a bad motor nount or a part of the exhaust system touching the body somewhere. OR, an exhaust hanger without a rubber isolator.

Would a Torque Converter going bad not be a possible cause?

[jeno]

How can you tell if you have a bad torque converter?

[M & J]

Could be a wheel bearing. Back to the center support bearing Rick talked about.

[Rickf1985]

A torque converter would be engine speed related and not road speed related. It would also make noise when sitting still usually in neutral or park. There is a list of 20 things it "could" be. what you are describing is usually in the driveline. If you start thinking about everything it could possibly be you will go nuts. You have the check the most common and normal problems first.

[Hahn007]

I agree Rick.
I'm going to start by temporarily removing the tail stock mounted parking brake drum and seeing if anything improves. It is definately road speed and not engine speed problem. I know this because shifting trans into neutral going down hill at speed problem is still there.

[DRMousseau]

A quick and through tire and wheel inspection is free,... make sure there is no unusual "cupping", shoulder or tread wear, no unusual swells in the tread, no bulges or "dents" in the sidewalls. Look for any loose lugs or missing lugnuts, and make sure wheels are properly mounted and spaced. Being through means getting each side off the ground for inspection and allows a simple check of brakes and wheel bearings. Make sure vehicle is well supported and other wheels blocked to prevent rolling. Your description sounds like a possible wheel bearing issue, and not uncommon on those rear axles. When were these last inspected?? When was fluid level in axle last checked???

With one rear side off the ground and inspected, place in neutral and inspect driveshaft assembly,... it should easily move to check u-joints and support bearings. If u-joints have no grease fitting, then they are originals, and are packed with grease and installed at the factory when new. You can expect to replace these originals near 80,000 miles or so since they cannot be easily re-greased and maintained. If grease fittings are present (on some OEM), then take the time to inspect and grease well. All new replacement u-joints have grease fittings and are shipped and stored "dry". Grease them well AFTER installing and securing. I will agree with Frank that ALL u-joints should be replaced at the same time, cost and effort is usually minimal.

Including that parking brake in your inspection is certainly important, as is the seals and bearings that are exposed for a look see.

And WHAT the heck is a "tickity boo"?!?! Lol!

[Hahn007]

Very good points.
It will be at least a couple of weeks before I can work on the motor home.
I will post my findings then.
Rear diff fluid/oil is full. Checked it first thing after purchase and a couple times a year too.

[Hahn007]

Update:
I was able to get the centramarics installed over the weekend.

Checked for radial runout using a fixed point for reference. Wheels and tires run extremely true.

Wheel bearings are not loose.

Did notice that the center u joint is very worn. Slop is apparent both visually and by feel.
I am willing to bet this is the main source of the vibration.
Going to replace u joints and then road test.