Driveline Vibrations---Possible Driveshaft Issues?

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BBslider001

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I figured I would start a new thread here so as not to get the "front-end rebuild" thread convoluted. I have vibration from 60-75 mph consistently. There are a few things to consider here....I did not have this issue until....

1) I had all brakes and axle seals done about 6 weeks ago at a local shop. He ahd good reviews, so I took a chance. I figured it's just brakes and seals, right? UGH... This idiot mechanic who fancies himself a helicopter engineer thought that "skidding" the truck in his driveway at the shop would set the new rear brakes. He got it up to 30 mph and would skid it on the gravel. He had me do it once and I told him that wasn't doing anything but tearing up my truck. The truck drove like a Cadillac at 80 mph before this. Yes the front end was bad, but there was ZERO vibration on this truck. I drove it home from Colorado Springs to Fort Worth at 80 mph the whole way....smooth as can be. Loose steering yes, but smooth as can be. Now it vibrates. Starts at 60 and gets BAD at 75. It would shake the entire dash.

2) I just had the entire front end rebuilt....EVERYTHING including a new steering gearbox. Now it drives straight, no play in the wheel, and has 1 finger steering. It does vibrate less, but now with the front end so tight, I can definitely tell it is coming from the rear. I am thinking two things. The new drums are out of round or the ujoints/carrier bearing got "fubarred" with this guy and his "skidding" technique. From everything I have read with this kind of vibration, it is driveshaft related. The ujoints look okay on the lift, but they are originals. I can take it off and have it rebuilt with new joints and bearing at a local driveleine shop for about $300. I am heavily considering this just to knock it off the list and eliminate one possibility. I am also thinking of getting the drums turned or replaced under warranty because I have read that more often than not, they come new out of round and guys are taking them and getting them turned to solve vibration issues.

So, get the driveshaft rebuilt and replace or turn drums? I highly doubt I will go back to this guy to make it right even though I am convinced that something he did caused this. It's simple. It didn't have any vibration when I took it to him. After brakes and axle seals, it vibrates like an SOB. I don't want him to touch it. I'll take the loss and do it myself like i should have to begin with.

Any thoughts and opinions appreciated. Thanks for reading.
 

highwaystar

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If it's the drums, you should have vibration upon braking.
If not, it must be the driveshaft. When ujoints are replaced, the
driveshaft must be balanced before reinstalling. I vote driveshaft.
 

BBslider001

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If it's the drums, you should have vibration upon braking.
If not, it must be the driveshaft. When ujoints are replaced, the
driveshaft must be balanced before reinstalling. I vote driveshaft.
I crawled under there a bit ago. I have no carrier bearing. I thought I did. That's my other truck. Joints look okay and no play, but I know that's not the only thing. I thought for sure the CB would be the culprit, but since I don't have one, I am getting concerned this is gonna be something I can't figure out. One guy told me the rear end itself could be going out and causing this vibration. Never heard of that.
 

termite

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I crawled under there a bit ago. I have no carrier bearing. I thought I did. That's my other truck. Joints look okay and no play, but I know that's not the only thing. I thought for sure the CB would be the culprit, but since I don't have one, I am getting concerned this is gonna be something I can't figure out. One guy told me the rear end itself could be going out and causing this vibration. Never heard of that.
Double check the rear joint is seated correctly in the pinion side below the straps. I've had a less than good shop install it off center and create a nasty shake before.
 

Rustbucket79

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Wait what? Do you need to rebalance after a u-joint change?
Nothing Ive ever done, was that luck?
If it's the drums, you should have vibration upon braking.
If not, it must be the driveshaft. When ujoints are replaced, the
driveshaft must be balanced before reinstalling. I vote driveshaft.
 

454cid

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Wait what? Do you need to rebalance after a u-joint change?
Nothing Ive ever done, was that luck?

No, u-joints should be quite symmetrical. It's possible a new u-joint could have excess clearances though. I've heard that some u-joints actually come with diffeent thickness's of clips to adjust the clearance, but the ones I've purchased have not.
 

BBslider001

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I just got back from driving it. Now it feels like it's in the front end. Good grief this is maddening. I had the tires rotated and balanced twice. No change. I am beginning to wonder if I have a bad tire or two.....internal separation. I had that before on a Dodge 2500. It was maddening to figure out. Balanced them 4 times and finally a guy says "hey look at this". I don't see anything obvious, but dammit this has got to be somewhat easy to find. I'm at a loss. I dont want to keep throwing money at it and no dice. Arrgghhhh!!!
 

Schurkey

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HOW are you determining "Front" versus "Rear" for the source of the vibration?

"Skidding" on gravel would not cause a vibration unless he picked-up a million rocks in the tread and threw the wheel balance "off". Seems very unlikely.

Drums, when out-of-round, cause pulsation when braking. Drums, when out-of-balance, cause vibration. About the same with rotors and warpage/thickness variation/runout; versus out-of-balance. Consider removing the drums, having them installed on a "wheel balancer", and see if they're out-of-balance. If they are, they're defective and you should get "free" replacements under warranty. But you'll be out the cost of the labor to check the balance.

"Balancing" a driveshaft can be beneficial. They're balanced when manufactured, and the weights spot-welded on. The weights can be knocked-off. But don't forget about BENT driveshafts.

My Trailblazer had a terrible shake starting at 68 mph, worst at 73 mph, and gone by 80 mph. 2WD or 4WD made zero difference. At 70--75 mph, the mirrors were useless--they were shaking so much that there was nothing visible in them but blur. The shop told me the rear driveshaft U-joints were OK. They were kinda puzzled about what was causing it. I took it home, removed the driveshaft, and found that the rear U-joint was totally wiped-out. Hauled the shaft to the local driveshaft specialists. They crammed in both U-joints because they don't foook around with "used" U-joints. Put the shaft on a lathe and discovered it had warped/bent in use. They straightened it as much as they could. I think they said it was straight within .020. Put the shaft on, vehicle was totally smooth--to the point where it was smoother all the way down to 20--25 mph where I hadn't even realized that it had a vibration problem until it wasn't there any more.

This lasted about a year or two.

Trailblazer starts shaking again, same 68--78 mph deal. Pulled the driveshaft, the U-joints were still in beautiful condition. Got a different driveshaft from the Treasure Yard, stuffed a rear U-joint in the "new" shaft, and again the vehicle was smoother all the way down to 25 mph--and again I hadn't realized that it was vibrating at that low speed until it was gone.

If this ever happens again, I'm getting a larger-diameter shaft than stock. I'm convinced that the second vibration was not from the U-joints, it was from the warp/bend in the shaft getting worse.

IF (big IF) the driveshaft is the source of the vibration...you may need a new bushing in the tailshaft also. If the shaft is shaking the truck, that shake transmits through the rear axle and the transmission--that tailshaft bushing is getting pounded.
 
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BBslider001

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@Schurkey Man I am honestly going by feel as much as I can. It really seems to be at the rear and then after a few miles, the whole truck is shaking, so it's hard to determine. Sounds like I need to do u-joints either way and eliminate that. I'm also going to go buy a discount tire or other real tire shop to determine that my tires definitely are balanced and not damaged internally. I also planned to take it by the guy that did the brakes and see if he can check the drums for me because they are under warranty or at least be willing to provide replacement and eliminate that as well. So that would be u-joints, drive shaft, tires, and drums. After that I don't know what else is left other than the rear end itself.
 
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