Got the U-joints done about a month and a half ago. That made a small vibration a little bigger, but I've just been able to ignore it as long as I wasn't going any of a few speeds (54-58, 84+ mph). Yesterday on my trip home (highway) it was there most of the trip, regardless of speed. Today, when I was going about 72, I turned off the radio just to see how loud it is, and boy was I surprised. I went up to 74 mph and holy HELL! The change in my cupholder was attempting to flee and my sunglasses were sliding down my nose!

I haven't ever gone off road with it. 2001 F-150 screw 2WD, about 210,000 miles. It was suggested before that my driveshaft needed balancing, but I didn't go for it because I was not only afraid that that might not be the solution, but also, I didn't have the money. Recently, someone said it could actually be a problem with the u-joints (seeing as that installation of new ones brought about the vibration.) Please, any help to calm my nerves! Its a Friday night and I have to drive it this weekend, not to mention I don't have the money...

Edit: Here's a picture of a nice little ding I just found. Looks fresh to me, but what do I know.

 

Did you mark the original position of the drive shaft at the pinion yoke? If not you good have changed the balance relationship. Can't see the pic so can't tell if it's new or not

 

That ^ and inspect the shaft for clean places where a weight might have come off. Also look for dents in the shaft.

Good luck.

 

I didn't do the work, I had a very well trusted local garage do it for me. I intend to take it back to him ASAP, I just wasn't able to now because the vibration arose on a Friday afternoon about 5 minutes after closing time. lol

I was not able to find any spots where a weight might have been, but I was also not sure where I should be looking--being a 2 wheel drive, its a very long drive shaft and I don't know if a weight would be near the ends, middle, on the ends, etc. The only thing I found was the knick that I took a picture of (that doesn't seem to want to show up...) I couldn't find any dents, either.

What is peculiar is that the vibration just got so much worse in the last 2 days. I didn't drive over anything; the only thing I can think of is that a rock or something in the road hit it and made the knick I photographed. Note: the knick is basically on the end of the driveshaft where it meets with the diff.

 

You got new u-joints on both ends of the drive shaft right? I would take it back to the shop as soon as possible and just tell them that it's gotten worse sense they worked on it. They should at least diagnose the problem for free

 

Diagnosing it for free isn't the issue; I know he will do that much.

Next question. Assuming the problem is a drive shaft unbalance, how much should I expect to pay to have the drive shaft removed, balanced, and reinstalled?

 

Could you remove it and reinstall it on your own? All there is to it is taking 4 bolts out of each end and it's off. All you need is a socket wrench or a box wrench. It's very easy. You don't even have to jack the truck up. It would save you an hour of labor cost if money is tight. I have a 4x4, and I took my smaller front drive shaft out and took it to the shop to have it balanced. It would probably run you $50 or so to have it balanced if you take it off and take it to the shop. Unless it costs a lot more to balance a big drive shaft like that, but I don't know why it would

 

See problem is, if I take the drive shaft off myself, I'd have to carry it to the place to get it balanced :P I can problem talk him down on labor cost.

 

Nobody can give you a ride to take it?

 

Even if they could, I have absolutely no idea where to take it. The 4 shops I called at home don't do it. The guy I have work on my car is where I go to school, not at home. I am currently at home.

 

Oh i see. Well there's no way you'll be charged more than one hour of labor to take it out and put it back. They may only charge you half an hour

 

[QUOTE=dean.mohr;4650031]I didn't do the work, I had a very well trusted local garage do it for me. I intend to take it back to him ASAP, I just wasn't able to now because the vibration arose on a Friday afternoon about 5 minutes after closing time. lol



I was not able to find any spots where a weight might have been, but I was also not sure where I should be looking--being a 2 wheel drive, its a very long drive shaft and I don't know if a weight would be near the ends, middle, on the ends, etc. The only thing I found was the knick that I took a picture of (that doesn't seem to want to show up...) I couldn't find any dents, either.

What is peculiar is that the vibration just got so much worse in the last 2 days. I didn't drive over anything; the only thing I can think of is that a rock or something in the road hit it and made the knick I photographed. Note: the knick is basically on the end of the driveshaft where it meets with the diff.[/QUOTE]

That is around the area where the weights would be welded on, they are usually found at either end of the shaft.

 

That's true. The weight might have fallen off and it appears to be a knick

 

I was able to see your picture (somehow showed up in my email... from flickr) The nick looks like someone may have dropped the drive shaft on the yoke. The weight is the rectangular piece of metal welded right below it. I dont think the nick is enough to unbalance your shaft. Check to make sure all of the split ring keepers are still in place and none of the u-joint caps have fallen off

 

The OEM tag around my rear drive shaft says "scrap if dropped".

I am also experiencing vibration, I think it's either drive shaft or rear axle. Gonna put the axle on jack stands and run my dial indicator at different places on the shaft, then gonna do the same to each rear wheel hub.

Anyone know what the drive shaft runout should be?
'08 5.4l 4x4 Scab 5.5ft box