Hi everyone,

A little help here. Truck is a 2001 3500 2wd with approx. 180,000 km on it, with 95% of that being highway driving pulling a trailer.

I have some kind of vibration going on. Normally, the truck is always loaded down with a trailer (approx. 10,000 lbs). I took it out for a spin yesterday just empty and noticed a light vibration. However, this vibration is only noticeable in a few very specific situations. Essentially, if I am curving to the right at hiway speeds, I am able to feel a very light continuous vibration (almost like a humming type sound). Also, if I am on the smooth hiway and hit a decent bump (the kind you can def. feel) the humming noise returns, but not continuous, kind of as the truck bounces, the humming noise follows the bounces. However, tf I am driving just straight down the hiway, or curving to the left, everything is perfect.

I crawled under the truck yesterday and checked the u joints. Put the truck in neutral, and set the park brake. Was not able to shake the drive-shaft or anything like that, but was able to just barely rotate (turn) it just a little little bit. Is this the right way to test the u joints? Is this a sign they might be on their way out?

What else could I check?

Another thing that crossed my mind. Last summer, while I was pulled over one night, I noticed some weird wear on my front steer tires (with some cupping going on the passenger side steer tire (right)). Took it in and of course, ball joints needed replacing. Had those replaced and got an alignment done. However, I am still running the weirdly worn steer tires (they're not that bad, but the difference is defiantly noticeable. However, they were only 2 yrs old as of then, so still have em...). Could it be that the crooked worn tires are forcing something out of alignment, creating this noise?

As I mentioned before, normally I pull a trailer, 95% of the time highway. I never really seemed to notice this vibration while loaded. Just when unloaded? Is/would there be a reason for that?

Any help is greatly appreciated.

Thanks,

 

Barndog, trying to diagnose intermittent vibrations is one of the least enjoyable hobbies around. This first suggestion is likely a red herring but lets get it out of the way. Rotate the tires front to back, thereby moving your strangely worn front tire away from the steering gear. If the problem goes away, you know your problem.
Since you have a 2wd, we can rule out issues with front u-joints. That is nice, because u-joints can cause issues. That also points us toward the only other thing I can think of. I suspect you have a front wheel bearing going out.

As I sit here typing, I just came up with one other possibility. I had a weird vibration in a rear wheel drive car once that I only felt or heard when turing in one direction. It turned out I had a spider gear failing in my differential. Let's not make thing complicated yet though. A good rule to follow - when given two possible solutions to a problem, the simpler one is usually the correct solution.

So, my uneducated guess is a wheel bearing.

Now time for the more experienced members to chime in and give you real help

 

Good advice from Tallguy. As you steer to the right, the truck leans and increases the load on the left wheels. If you have a failing left wheel bearing, those are the conditions where you will usually hear it more. As mentioned, if you have weird wear on the front tires, I would first rotate them to the rear and go for a drive to see if the noise changes. If you are real lucky, the suspect wheel bearing may be worn enough that you can feel some play in it when you jack up the truck. Usually however, they won't show any play until the noise is more pronounced.

As far as inspecting your u-joints, the method you describe is great for finding a loose joint. However, if you have a seized joint, you may have to remove the shaft completely from the truck and exercise each joint through its full range of travel in each direction to find one that is sticky or won't move.

Hope this helps.

 

I would also check the center support bearing in the driveshaft along with the u-joints.

 

Both times my ujoints went south I could not move them. I had to pull the driveshaft and twist them. They were gritty, with rusty dust around the seals.

If your truck is generating the vibration while turning or coming out of one, I am thinkin wheel bearings also....uneven wear is also affecting whatever is going on.

 

I would generally lean towards u-joints but if its doing this more while you're slightly turning then I'm thinking more wheel bearing or just irregular tire wear causing feedback.

One thing to ask is, is the vibration you're feeling fast and harmonic or slower and more wobbly? That makes a difference.

 

I would say it feels more fast and harmonic and the vibration is definitely on the front end. I can kind of almost feel it through the steering wheel, not through the seat (although it is very slight - but continuous - not intermittent unless you hit a big bump and the truck bounces). I should also add that it is most prevalent when at a cruising speed (not accelerating - any steady pace from about 20-60+ mph - and of course only in the situations described in the original post). When accelerating, whether turning or not, regardless of speed, the humming noise/vibration is either non existent or I just can't hear it.

My gut feeling is that it is the irregular tire wear on the passenger steer tire as the outside edge/corner of the tire is worn down quite a bit more when compared to the driver's side steer tire (this being due to the ball joints being worn out and being out of alignment previously - I discovered this of course after I bought new steer tires). Rotating the tires isn't really feasible as I have grippy mud/snow tires on the rear duals and highway steer tires on the front (since I am mostly highway, but then have to pull off road onto a grassy field or mud hole with the trailer, etc.).

If it turns out to be the case of irregular tire wear, I may just have to live with it for a couple more years until new tires are worth it. I just want to be sure that it's not something like a wheel bearing or u joints - something that could leave me broke down somewhere (try being broke down in the middle of Saskatchewan - good luck finding a repair shop...). I haven't had a chance to check the wheel bearings yet, but it'll be the first thing on my list once I am done these exams!

Any other ideas on things to check?

Thanks for the help everyone!

 

If its more harmonic then its likely not related to the tires since tires spin too slow to create a harmonic "feel". That said, if the tread is irregular then they can make more a harmonic "noise" than a vibration at higher speeds. I'm still leaning towards a wheel bearing. The only thing which would cause a vibration type feel in the steering wheel would be warped rotors. You should also feel it in the brake pedal too though.

 

So, I checked the wheel bearings last night (both of them). I don't think it's a wheel bearing though because there isn't any play in either on of them and there is no grinding noise at all when I rotate them by hand.

Is it possible that they may have dried out due to the dust seal failing?

Haven't had time to actually take out the drive shaft and test if the u-joints are tight, although I'm doubtful of this as the noise isn't that bad (last time I had a u-joint go out on the work truck, it was a very loud growling, screeching, squealing noise - quite obvious)

I know nothing is wrong with the diff (just did a fluid change and inspected gears - they are like new, and so was the fluid that came out!)

One thing that crossed my mind. Is it possible that there is a brake shoe or something that is sticking, or rubbing? The only problem with this is that I don't feel anything when I step on the brake.

Any other ideas? Thank you in advance.

 

Since your truck is 2wd and you feel it in the front, especially when turning, then its likely not u-joint or differential related. I'm sure its just uneven tire tread or rotors with a light warp to them. Doesnt mean you have to feel it in the brake pedal either as much as it causes the calipers to move side to side which gives a vibration type feel. Generally too if you have a sticking caliper or dragging pad then you'll see it wear faster than the other pad in the same caliper.