Strange vibration felt in cab

[ICAT]

I have a strange vibration in the cab. It only happens at around 30mph and it stops at around 15mph. The only thing I have done is flip the front upper spring purch. when the vibration started I flipped it back. It also only happens when I'm driving and I hit a bump in something. I'm leaning towards the right front hub or the transfer case. It stops if I engage front end. Their is no lose of steering, brake, clutch, transmission performance.

Any thoughts

 

[gungearz]

It needs more double a's... Its not viberating hard enough.

 

[RAYZER]

Check all of your drive shaft flange bolts.

 

[ICAT]

Checked all the drive shafts, and hubs for excessive play.

 

[gringeltaube]

Sounds to me like you're experiencing what's called "Wheel Shimmy" or "Death Wobble".
Many things can cause this - tires not round; un-balanced; loose steering components, etc..

Good reading here, in this thread...

G.

 

[ICAT]

Their is no vibration in the steering wheel. I have no performance issues with the steering, brakes, clutch, or trans

 

[ICAT]

Well I had friend ride with me to day and we believe the vibration is masking the a problem with the front end. I'm thinking a differential side gear or bearing.

 

[rchalmers3]

Does steering the truck left and right while the wobble is occurring make any difference?

Rick

 

[ICAT]

There is no wobble, however I noticed turning right the vibration would "slow down" compared to turning left. That is why I'm am looking at diff side gear

 

[rchalmers3]

It's a long shot, but you may find a problem in the knuckle area: stub axle not floating properly, worn bushings, worn out cross.

Regarding a differential issue, have you confirmed the tires are a match and the pressures are equal? Yours will be the first I heard of with a diff issue, other than faulty pinion bearings.

Rick

 

[poppop]

My Duece had a problem like that and it urned out to be a bearing in the transfer case. It got worse and worse till I lost low range. That narrowed it down to the transfer so we opened it up and found the bad bearing and other damage caused by the bearing going bad.

 

[RAYZER]

You could pull your front axle caps to disconnect your front axle assembly so it doesn't turn under driving conditions , this would narrow it down some.

 

[ICAT]

I had all the covers off in the cab to help with diagnostic. When the vibration starts, the transfer and trans both have no issue. I was going remove the front hub next but I'm fight a sinus infection today.

 

[ICAT]

OK, today I got an extra set of hub milled out for the front to free wheel. No vibration. I'm going to drive it longer to verify but I'm looking at the front diff.