Noise at speed

[Fiver]

OK, I'll try to describe this as accurately as possible. Bought the truck new in 03, HO auto 2500 SLT, 4 dr shortbed, 77500 miles. For years now I have detected a rythmic/cyclical drone type sound when on the highway. It's not overwhelming or anything but is definitely there. I can detect no vibration and I run stock tire size, no lift kit, or drivetrain modifications other than a DTT trans installed in 2009. That made no difference. Ball joints and hub assembly's are near new (XRF and Moog), no change. Same for tire changes. The only way I can relate the condition is to say it sounds somewhat like I am running over alterante strips of rough and smooth pavement, although not very loud. Seems to be a little bit louder though the last couple of years or so. No change when I'm towing my 6000 lb trailer. Any of you guys out there ever experienced this or had a similar issue? I talked to a couple of local mechanics who had no idea. Thanks for any feedback.

 

[AH64ID]

What shape are your u-joints and carrier bearing in?

 

[Prairie Dog]

Another vote for the u-joints. If you haven't replaced them yet then it's just about a sure thing that one or more are bad. You can't tell by just looking at them (unless they're super bad), they have to be removed.
Your lucky, the vibration is a warning!

 

[sag2]

Sounds like the 68-72 mph quad cab drone. It is the combination of the natural 3rd order engine firing frequency and a first order drive shaft vibration. They intersect at that speed with 3.73 gears. I fixed many trucks back in the early days of 3rd gen, but there were several I could only make worse.
If you want to try something free and easy, mark the rear drive shaft to pinion yoke position. Remove the bolts and reinstall the shaft 180 degrees from where it was. Evaluate if better or worse. If better but not gone use hose clamp to fine tune the drive shaft balance.
Search for drive line vibration, I wrote up the diagnosis and repair in great detail several times.

 

[Fiver]

I'm thinking it is not the u-joints as the truck has been doing this since way before they should have started exhibiting wear. Sounds like sag2 may be on to something. Have never heard of that but it sounds logical. If the rotation does not work or makes it worse, is a driveshaft balance the solution?

 

[AH64ID]

Some joints last a long time, and some don't. The carrier bearings are also prone to failure.

Where in Idaho are you? Six states in boise can build a 1 piece shaft for just a little more than 3 new joints and a carrier bearing.

 

[sag2]

Getting the shaft balanced off the truck will generally be a waste of money. It needs to be balanced on the truck.

 

[AH64ID]

I presume this frequency you describe is with auto's at that speed?

 

[Wayne M.]

I had a buzz developing at highway speeds. I had to work a special location where I had to back up along a long wall tight. Well As I was pulling out from that spot, going slow, I heard THAT SQUEAK SQUEAK. Ididnt even think about it. I got greasable precisions, and upon inspection and disassembly, the rear one was toast. Buzz was gone.

 

[rscurtis]

Try removing the front DS and see what happens.

 

[Fiver]

First of all, I'm in SE Idaho but go to Boise often. Six States sounds like a viable option. It seems now, based on your replies, that I should take the simple approach first and look at the U joints/carrier bearing. I can hear it at lower speeds on quiet pavement, just not quite as evident. Can't hear anything at 10-30 mph. This really helps, I appreciate all the replies.

 

[K5IP]

I agree with the u joint or drive shaft possibilities. But, you might want to look at the hoses from the power steering pump to the brake system. One of them should have a damper weight on it (several pounds). I chased a vibration problem for a long time before I found this. If you do not have a damper weight, try tying the two hoses together with a zip lock (temporarily) and see if it makes a difference.
It only takes a minute to look!
Rog

 

[Fiver]

Thanks K5, I'll have a look.