Community Forums

ginger9dog · 05-03-2015, 01:09 PM

When cold (as in not driven in a few days) I get a vibration in steering wheel. It is always around 1500 rpm. 2006 discovery with freightliner 38000 miles. Does decrease after driven awhile.

TeJay · 05-03-2015, 02:34 PM

People will be asking for more information. Brand and miles on the tires? Any work done recently, like suspension, alignment, tires rotated, tires balanced?? Is the coach new to you?? If not when was the last time you drove it and did it do it then?? Did you run over a curb or hit anything like a cow, horse, (just kidding about the horse).

When vibrations do occur they will usually occur at about the same RPM's or more correctly road speed. Engine RPM's and road speed are different. When pin pointing any vibration we have to separate engine speed from road speed. Your engine can be going 3,000 rpm's and you are not in gear. You can get going 60 MPH and put the engine in neutral and drop the engine RPM's back to idle.
Road speed involves, tires, wheels, rotors, and drive shaft, and differential.

Years ago when the nylon belted tires first came out some were known for getting a flat spot on them from setting which would smooth out after they got warm. That is not something that I have heard happening for a long time. Most everything is steel belted and radial in design.
Be more specific on the vibration: Is it engine rpm's or road speed??? Answer the questions above and you'll get answers.

TeJay
TeJay

FIRE UP · 05-03-2015, 03:37 PM

Tejay
You and I think so much alike, I could have very, very easily wrote the same exact answer to the OPs question as you did. More info is needed and, correlating vibrations to engine RPMs vs Road speed, is not easily done.
So, to the OP, yep a bit more detail of speed, gear in trans you're in and whatever else info you can provide would be more helpful so that we may help you easier.,
Scott

TeJay · 05-04-2015, 06:20 AM

And a, "Good & Wonderful Morning to you as well, FIRE UP!!!" I'm sure our DW's would have many, many comments regarding us thinking alike. LOL

Take care,
TeJay

ginger9dog · 05-05-2015, 05:57 PM

the vibration ALWAYS related to rpms. decreases as motor home warms up, but never goes away completely. tires been balanced, not out of round, the vibration quits if coasting or sitting still and run engine at 1500 rpm. it must be pulling at least a little bit at 1300-1600 range to vibrate. It appears to have a steering fluid filter below the holding tank. freightliner chassis, Fleetwood discovery. thanks for any help..

bobguigley · 05-05-2015, 06:10 PM

We had a similar problem, two new front tires solved the problem.

FIRE UP · 05-05-2015, 10:52 PM

Quote:

Originally Posted by ginger9dog

the vibration ALWAYS related to rpms. decreases as motor home warms up, but never goes away completely. tires been balanced, not out of round, the vibration quits if coasting or sitting still and run engine at 1500 rpm. it must be pulling at least a little bit at 1300-1600 range to vibrate. It appears to have a steering fluid filter below the holding tank. freightliner chassis, Fleetwood discovery. thanks for any help..

Now it's beginning to sound like an out-of-balance driveshaft. You say it's always related to RPMs but and, you must be "pulling", assuming you mean putting a load on the drive train. But,

1. If you're in neutral and rev to 1500, no vibration
2. Quits if coasting (no load on drive train,) correct?

Now, let me ask you this. Has anything changed recently in the coaches handling? Has anything changed in it's stance? That is, is it riding as high as it always has? Or, is it lower?

You see, ride height is predetermined at the factory and, is set, based on certain parameters. When the ride height is correct, the drive line angle is correct too. If the ride height changes for some reason, now your drive line angle has changed too and that, can present a problem in terms of a vibration. And normally, drive line issues are more noticeable when "pulling" or, when power is being applied. But, they tend to relax when no power (coasting) is encountered.

If, for some really odd reason, you lost a drive shaft balancing tab, (usually a small piece of metal tack welded to the drive shaft for balancing purposes), that can have anywhere from a small to a really pronounced effect, depending on how out of balance it is, without the tab. But, all this is pre-supposing your drive shaft is the problem.

Since you say the vibration is not there if, you're in neutral and no load and, rev to 1500, Then I kind-a assume it's not engine related. So, that's about all I can add.
Scott

TeJay · 05-06-2015, 07:07 AM

FIRE UP,
You took the words right out of my mouth LOL.

There's only two things I'd add. Poster #6 referenced tires. You could put two rear tires up front just to see if there is any difference. You'd be surprised how often a tire can & will cause an issue even after it's been balanced & checked for run-out etc. Just because a tech checked & balanced your tire does not mean that it was done correctly. It's just a sure way of eliminating something that we believe is not the problem.

CASE IN POINT!!
Two years ago I bought a used pick up. The steering was sloppy. I checked the steering linkage & both ball joints all was well. OK so what?? Well I taught how to do that for 35 years. I can diagnose a loose or defective steering system in my sleep. I would have sworn & did that when I took it back to the dealer that all was in great shape (so I thought). The tech found a worn pitman arm. He took me out in their shop & showed me. I was shocked. Why didn't I see it??? Well I just don't know but I missed it & I'll admit it. They replaced it & all was well. I screwed up!!!

The worst mistake many, many techs make is to assume that a particular NEW part that they just installed is not the problem because it is NEW. NEW does not always mean GOOD.

Second point is this. When trying to diagnose any issue move one step at a time. If as, FIRE UP has suggested there might be an issue with ride height then get that verified as being correct. It's very possible that a balance weight has come off the DS. Get it checked. Don't jump to something else until these items are checked. Diagnosis involves step by step testing to verify and determine if everything is within operating parameters.

FIRE UP's point about, "No vibration when running at 1,500 RPM's & the coach is setting still" is critical & well made. All parts that are spinning when moving down the road are not turning. That distinction is most important when diagnosing vibrations. It was referenced before but now it's been explained very well.

When diagnosis is not done correctly I like to refer to it as, "Chasing your tail." You get nowhere because your going in circles & not down the proper path.

Best of luck & please do keep us informed.

TeJay

ginger9dog · 05-06-2015, 08:31 AM

I took mh to freightliner in Gaffney sc they checked ride height and drive train and found no issues. remember that the condition changes so much from cold to normal that it has to be temp related somehow. when in Gaffney the mh would not vibrate for the tech to feel it. it had sat overnite and the weather was cold the am he drove it. The only thing he found wrong was a grease fitting was not letting grease into joint.

TeJay · 05-07-2015, 06:28 AM

OK you've had the vehicle ride height and drive train inspected again. Lets assume that the FL technician did a good job and did not discover any issues. He also did not feel the vibration even after setting for the night. Lets think about this for a second. You just said "the condition changes so much from cold to normal that it has to be temp related somehow."

Ok, it's temperature related. If there's something in the spinning drive train that when it warms up it no longer vibrates how can that happen??? Metal parts will change some with heat build up but not a vibration. If something metal (drive shaft, U-joint, drum, rotor, differential ring or pinion gear, tire rim, wheel cover, hub, center support bearing and any other spinning metal part that I may have forgotten is out of balance at 20 degrees it's still out of balance at 80 degrees.

The only spinning part not metal that would change shape from heat build up enough to cause a vibration are the tires. Since the ride height and drive train have been checked I'm leaning more towards the tires because of the heat issue. If I'm wrong so be it. But that's what reason points me towards.

TeJay