Possible Driveshaft Imbalance??

[RobR]

Greetings,
From the start, our new (July) 26.5 ft Lazy Daze (E450 Ford Chassis) has had a vibration at highway
speeds. It is DEFINITELY not tire imbalance - it's much higher
frequency - plus I've had the tires checked. The vibration is like a rumble
that is most pronounced amidship. I had to disassemble the power
converter to put some dampers on the sheet metal as that was making
quite a racket with a noisy resonance in response to the vibration. I'm
thinking improper driveshaft balancing from the factory (Ford). Has
anyone ever experienced this?
Thanks.
Rob

 

[Frank B]

Rob:

>It is DEFINITELY not tire imbalance - it's much higher frequency<

Then driveshaft or one of the 'steady bearings' (if your unit has them) is probably a good guess.  I have such a vibration in my 94 Chev K1500 only when 4wd is engaged.  I'm going to have my mechanic check out the front driveshaft for the same reason.

Frank.

 

[Ron from Big D]

Could also be an improper driveline angle.  Not normal, but worth checking with the chassis manufacturer.

 

[John From Detroit]

There are many possible causes..  Used to be when I got that kind of vibration on the Dodge B-250 I used to drive on occsion... I knew to drop in the parts store and get a new U-Joint.

Now, as it happened the B-250 used 2 different rear U-Joints depending on just which one you had.  One was about eight bucks (back then) and the other 20... Being a dedicated follower of MURPHY I knew which one to pick (the more expensive) and sure enough.. It fit (the other one would not have)

Same on some older cars (NOTE: I tend to drive vehicles till they rust apart,  My current "Car" is a 1992 Lumina APV (that's All Plastic Vehicle) it's on it's 2nd tranny and engine, I can't tell you how many times we have re-done the brakes (2nd set of drumbs, 3rd or 4th rotaters) but it's not got a rear U-Joint so that's one problem a FWD vehicle will never have... It does have one axel that is in 2 parts,,,, but that is how Remco made it

 

[RobR]

Thanks everyone for the advice!
Rob

 

[Chet18013]

I had the same type of variation in my Dodge 4x4 diesel 3500. It indeed was the drive shaft.

The drive shaft on this truck, because of the extended frame, had 3 u joints.  Found one place that did car drive shafts and they could not handle a 3 u joint, 2 piece drive shaft.  Had to find a truck frame shop that had a long enough balancer to do the entire shaft in one operation. If  you go to a shop to get it balanced, be sure and tell them it has to be done as an assembled 2 piece shaft. Some places will tell you that doing each section separtely is OK.  Don't believe them.

Chet18013