Weird Vibration

[DarrylGF]

In my 99 National Tradewinds 7370 when I am going down the road at speed limit or usually when backing off the throttle I get a weird vibration. Sounds a bit like hitting the rumble stripes on the side of the road but not as intense. It will also do it when corning to some extent. Tires are not worn and the steering seems tight with little play. I had a Peterbuilt mechanic look underneath and he said everything feels tight. Does any one use those mercury filled wheel balancers? If so is it worth it? Some are filled with fine sand or something or is it just as affective to have the front wheel balanced?
Also another question. Has anyone ever installed a set of slideout locks made by HWH out of Moscow IA? It looks like it would beat having to put those jack bars against the wall and the slide inner frame.

Thanks, DarrylGF
99 Tradewinds 7370
No Toad yet

[TropiCal-Tex]

When I replaced my tires at Camping World, they used the "sand" inside the tires, and assured me that it works just as well as adding weights (old school) balancing.
After a year not, my personal opinion is that I will never let them do that again! Even though they added the special gizmo at the valve stem to keep the balancing granules out of the valve stem, and to let any water vapor bleed off before it gets into the tier when filling... I have two tires where I lose anywhere from 15 to 50 lbs of pressure when stored for as short a time as two weeks. Since one of these is an inside dual, I have to pay close attention to my tire pressure now.

Also, you have to drive a ways at speed before the balancing starts, so it feels bumpy until the "sand" gets distributed.

[Gary RVRoamer]

When backing off the throttle a bit? Sounds like a drive shaft vibration to me. Possibly a worn or out of balance universal joint.

Tire balance would be a constant vibration at some particular speed (or a set of speeds).

[Minisprint]

Sounds like a universal joint or carrier bearing

[DarrylGF]

I had Peterbilt check everything and he said it was tight but he didn't test drive it. I need to get someone to go with me on the freeway. I thought the drive line was just a bit sloppy myself, you know the spline area. Not sure how much clearance can be there. Thanks for the input.
I was surfing thru and saw where Dewey Clausen showed the pics of the cracked weld. I have the same problem. Also he is the one who pointed me to RV Custom Products for the 12v distribution panel. Sure learn a lot on these forums.
DarrylGF
99 Nat. Tradewinds 7370

[DarrylGF]

I was just wondering since the drive line is so short being a diesel pusher could the vibration come from there? I even feel it in the steering wheel. I ask the better half if she feels it and she always says no and to quit looking for problems. I had a knocking noise once and she didn't or wouldn't hear it and my son in law finally rode with me and found it was the front roof vent not pulled down tight!
My tires are wearing fine so don't think it is tire balance. I just can't understand it as it is intermittent and not very pronounced but enough it bugs me. I shouldn't let it worry me as I have so many rattles and knocks one more won't matter. Just rattling on.

DarrylGF
99 Tradewinds 7370

[John-D]

Quote:

Originally Posted by TropiCal-Tex When I replaced my tires at Camping World, they used the "sand" inside the tires, and assured me that it works just as well as adding weights (old school) balancing. After a year not, my personal opinion is that I will never let them do that again!

After a few years of reading about Equal and Dyna Beads and such I finally figured out how they work. I can now explain the theory.

However: My position on that is this: You are a WISE MAN to refuse to ever let 'em do it that way again.

[Intruder01]

I agree about putting equal in the tires. I did it when I bought new tires about 2.5 years ago.... nothing but problems afterwords... !!! I had my local tire shop take it out put new valve stems in and balance the tires with weights. Everything is back to normal !!!

[speed racer]

It could be a bad ujoint trying to lock up or it could be something as simple as the drive shaft alignment.

[snl2106]

Doesnt have to be a loose U Joint to be bad. Can be rusted inside from lack of lubricant. they get tight and vibrate. youll feel it in the seat of your pants when driving. Also make a noise. The Carrier may look good also but the rubber isolator can be weak due to age and degrigation of the rubber. Did you have the gear oil changed in the Diff as well? When turning a corner and you get a little viberation and you have a posi. unit, you may need to add a friction modifyer to the diff. Just a few ideas that I have seen in my day to day work with vehicles

[DarrylGF]

With my rear engine diesel the drive shaft is only about 2-3 ft long. There is no carrier bearing. There is some slop however with the spline. Just a minute amount. Not sure I spelled minute correctly. I mean just a very small amount. Is there a tolerance with the spline? I know it needs room for grease and everything with the drive line looks like plenty of grease and no rust.
I am going to take it to Orangewood RV in Sun City, AZ and get a oil/filter and lube job done here pretty quickly as we are heading to Central CA and then on to Iowa and back home to Sun City West, AZ
I will see if I can get one of their techs to ride along and see if we can make the vibration appear.
Darryl

[snl2106]

Have them pull the shaft and check the u joints to see if they are tight and binding. I would not suggest a long journey with a driveline vibration as it can do more damage. You can ruin the output shaft bushing or if is bad enough the pinion bearing. Id get tis problem solved before it turns into big bucks. If isnt a ujoint or driveline problem check for a slipped belt in a tire. If i understood you right it happens all the time.

[quikduk]

DarrylGF,

When we got our NTU coach, we drove it back from SW Texas or about 1500 miles. We never had a DP before so the heavy bumble bee vibration I felt in my throttle foot and seat I thought (hoped?) was normal.

When we got home, I put the DP on blocks and crawled underneath. What I found was that:

1. The air leveling valves (all 3 of them) were leaking AND the ride height was adjusted incorrectly.

2. The drive shaft slip spline and u-joints had little if no grease in them.

I replaced the air leveling valves, adjusted the ride height per Spartan specifications, dropped the driveshaft, cleaned the splines and regreased them and replaced the u-joints with new HD ones and regreased them as well.

The vibration was instantly gone and the coach rode 500% better (1000% better after I installed the Koni FSD shocks).

If you can't safely check these items out, have a qualified shop check them out.

FWIW, the original u-joints (and shaft) are Spicer and are about $150 each ...so I went with NEAPCO which are identical in quality and are 1/3 the cost (and made in the good ole USofA).

[CaptBill]

I agree with the previous post, that your problem is probably ride-height, so I'd check that first. Otherwise, as others have said, it's probably a U-joint goin bad. I'd get those things checked soon.