bad vibrations developed on trip

[bbaley]

Hi all,
I have a really bad vibration I can't pin down - yet.
I can feel it at nearly every speed above 20-25mph.

It appears to be wheel/axle speed vibration but not 100% sure.
at 50-55 on freeway it is worst. 60-65 a bit less, and varies above that.
Feel it in the steering wheel, and pedals, vibrates rear-view mirror.
Can "hear" it as a loud GRRRRRR.

It started on a 1100 mile trip from Portland, OR to Sacramento, CA.
I developed a loud whistle/whine - then vibration. Assumed driveshaft. took it to a truck shop. they sent out the rear driveshaft for U-Joints and balance. they also re-built my driver side front wheel hub.

nasty sound went away but not vibration.
I ran the trip without my front drive shat which is having u-joints/CV rebuilt.

Since these two repairs didnt fix vibration, I stopped on way home and had the wheels/tires rotated and balanced. still there.

The vibration for the most part does not get worse or less when accelerating or coasting, except on bumpy road surface is very amplified (like on alligatoring) more than youd expect from just change in surface.

I have Toyo M/Ts - which are fairly worn - but I am used to and in tune with how much vibration/noise they give me.

The vibration does NOT cause the steering wheel to bounce side-side - just vibrate with rest of truck. There is seemingly no vibration when stopped and engine running - except it "seems" a bit louder than normal.

Engine seems to run just fine, smoothly. I got my standard 17.5 mpg on the trip not babying the speed/hills etc.

The mechanics who did the rear driveshaft and hub, noted my ball joints are shot and need replaced. Having had bad ball joints before and done a bunch of recent reading on it - it seems like a possibility - but it doesn't affect steering and is at nearly all speeds.

The truck is a 2009 Dodge Ram 2500, Cummins 6.7, 4" lift, 17" wheels and the Toyo M/T's.

Can anyone help add to the list of possibilities I might get checked out and educated on ?

It seems like a bad tire/out of round, etc. could be a possible - if the (Les Schwab) kid who did the rotate/balance was maybe just in a hurry - but THAt bad ??? I plan to jack it up in AM and check for round on my own.

Also my front driveshaft goes in tomorrow, I'll have that mechanic drive it too.

what do bad bearing on rear axle feel/sound like ?

any ideas greatly appreciated !

 

[MiRamDriver]

In a worn tire, the belts can separate long before you hit the wear bars on the tread and cause this exact problem. My money would be on that.

 

[Burla]

Track bars and sway bars are always suspects, and it sounds like you need new tires and ball joints regardless. Are all you lift parts tight, steering stabilizer too? Even shock mounts can act like this as well. If you go way down on air pressure you can diagnose if it is a tire problem. That at a minimum would change the characteristics of it. Is it in the front?

 

[bbaley]

belt separation

In a worn tire, the belts can separate long before you hit the wear bars on the tread and cause this exact problem. My money would be on that.

Stupid question, but wouldn't that be noticed when balancing them ?
(assuming semi-talented or caring individual).
Thats a learning question on my part ;-)

 

[bbaley]

good ideas

Track bars and sway bars are always suspects, and it sounds like you need new tires and ball joints regardless. Are all you lift parts tight, steering stabilizer too? Even shock mounts can act like this as well. If you go way down on air pressure you can diagnose if it is a tire problem. That at a minimum would change the characteristics of it. Is it in the front?

I will try the air pressure and see what difference it makes.
It's hard to tell if front/back or neither. it seems to be coming form "everywhere".

I didnt think about shock mounts. I will have those checked too.