I thought I would post my experience with my drive shaft.

My truck is an '04 one ton dually, with 187,000 miles. I bought the truck with 112,000 mi. The truck always had some what of a shudder from take off to about 15 - 20 mph. I never gave it much thought.

About a year ago, at about 150,000 mi., The u-joints in the drive shaft started knocking and rattling. No big deal, I had them changed at the local mechanic shop.

Just recently, it started having a bad shudder/vibration at all speeds. I crawled underneath the truck and inspected the u-joints. None of them were lose or worn that I could see. I kept looking and decided the carrier bearing was lose and had some slop. I got the bearing changed at the local shop again. The harsh, solid shudder went away, but there was still a vibration that made a whining noise at 60 mph.

I went online and did some research on drive shafts and decided my shaft might be off balance. I called a shop that specialized in drive shafts and machining, and they advised me that my drive shaft should be balanced. They could do it the same day, for $90, if I had it there by noon.

I didn't waste any time. By this time I was sick of the noise and vibration. I pulled both sections of the drive shaft out and had it there by noon. The two rear u-joints ( the same ones I replaced a year ago) were wore badly, so they replaced those and balanced the shaft.

The difference is amazing. No more shudder form take off. No noise at higher speeds. No vibrations. Drives smoother than it ever did.

For the record, I will never again change u-joints, and not have the shaft balanced.

My experience, for whatever its worth.

 

Thanks for sharing... I wonder how the shaft got un-balanced to begin with...?

 

When I do drive shaft ujoints I mark the ujoints so the shaft gets put on the same way. I have personal experience with drive shafts making noise after a ujoint change. All I did was unbolt the ujoint and rotate then reattach.


Steve. the eight is just tach welded on and sometimes get flung off.

 

interesting... I'll have to make a mental not to have the shaft balanced anyway when the joints are changed. I dont think I need it at the moment.

 

The first time the u-joints were changed, about a year ago at the local shop, they marked everthing and put it back together like it was. I don't think that had anything to do with the shaft being off balance. I believe it was off before then, and even before I bought the truck. Why it was off I don't know. Possibly a weight nocked off or something simialar.

I personaly would recomend having a shop change your u-joints that can also balance the shaft, as it only cost me $150. So, for not more than it costs, at least get it checked.

 

From my experience, driveshafts go off balance because of many different reasons. 1) the balancing weights fall off the driveshaft. 2) there is a change in angle of the driveshaft. If the vehicle undergoes a change in ride height (like lifting or lowering the car) you will most likely experience some shaking problems with the driveshaft. Or if you make a change at either end of the shaft (changing the transfer case, or rear differential, etc.) the distance may shift to either the front or the back. This puts the driveshaft in a different position than its original place and it causes balance issues.
I had a tranfer case put on my 98 Ram 1500 recently. The one I bought and had put on is much bigger than the original part. The size of the new part made it so the driveshaft angle changed to a steeper angle and I began to have shaking issues when I hit about 35 mph. I have yet to get the driveshaft balanced, but I am aware of the cause of the shaking of my truck.
Also, I have never heard that changing u-joints on a driveshaft causes it to get off balance. It doesnt seem like a possible cause. As long as it is a simple remove and replace job it should be fine. But I dont have any experience with balance issues after a u-joint change.

 

Changing of u joints is not going to unbalance a driveline. Nor is lowerin or lifting going to cause an imbalance. The liftin or lowering will change the driveline angle which can cause a vibration but its not a balance problem its a angle problem. Extreme positive or negative angles. The reason for them marking the driveline at the shop is to keep the driveline in phase. meaning the yokes are all in a line. if one yoke is slightly off a few degrees to one side or the other can and will cause a vibration. This is mainly caused when you pull the driveline loose from the slip yoke and dont put it back in phase when the driveline is put back in. In example if the truck is towed from the front and picked up. they have to pull the drive line so it doesnt burn up bearings in the transmission. when it gets to a shop and they have someone put the drive line back into the slipyoke and they dont pay attention it will get out of phase. Now on a single piece driveline its either going to loose a weight or get slightly twisted both of these can cause vibration. And like you found u joints will cause vibration too.

 

If you change a u joint and dont mark the shaft and yokes to match it can go out of balance it you don't line up all the parts the same way ?? my understanding is that when you take a driveshaft apart you are suppose to mark all the parts to make sure they all go back the same way?

 

Aslong as you keep the drive line in phase when changing u joints you wont have a problem. You dont really have to mark everything you can just line everything back up by looking at it. The main reason for marking is for a reminder of where it went so you dont forget how it went.