vibration, possibly u-joint -- PARTIALLY SOLVED
 

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post number 13 discusses results of the u-joint replacement

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99 silverado ext cab,
2WD 5spd manual
98k miles
tires have less than 10k miles
there is no North-South or East-West play in the front wheels

vibration between 40-45mph and again at 55-65mph
had wheels spin balanced twice at one shop, then a third time at another
still vibrates

First question - how precise is computerized spin balancing? Is this
typical: the mechanic balanced one wheel to 0.00, took it off the
machine, put it back on the machine. it was then off by 1/2ounce.
he rebalanced it to 0.00, then did the same test again. happened
three times. it was always off by 1/4 to 1.0 ounces.

Second - there is a tiny bit of rotational play in the u-joint next to the transmission,
major rotational play in the middle u-joint (most of it seems to be at just one of the
four points), and no rotational play in the u-joint next to the differential. Is any
amount of play acceptable or safe? How big a job would it be to
replace them myself?

Third, In neutral with the clutch out, there also seems to be very
noticeable play forward of the first u-joint. What might that indicate?

Fourth - how do you inspect the carrier bearing?

thanks in advance,
mike

RE: vibration, possibly u-joint
 

i found these websites for u-joint repairs:

http://www.stu-offroad.com/axle/ujoint1/u-joint-1.htm

http://forums.pickuptruck.com/ubbthr...=522046&page=1

http://tinyurl.com/yuzwe8 or: vib at 30mph

sat mech:: u-joint replacement

car care clinic: u-joints

RE: vibration, possibly u-joint
 

Dose it vibrate more when you let off the gas at higher speeds? If so then youre ujoint is bad

RE: vibration, possibly u-joint
 

The vibration between 40-45mph is fairly robust. it persists under accelleration, deceleration, clutch in, clutch out/in neutral, and seems to have about the same frequency in any gear (running at 40-45mph) (seems to be independent of RPM)

It then quiets down and is vibration free between 50-60mph.

However, this evening I noticed the vibration occuring during light or medium acceleration anywhere in that range 50-60mph

The 60-65mph vibration is present when driving at constant speed on level ground. It goes away when the clutch is in, or when it is out and in neutral.

I know the middle u-joint is bad, the the front u-joint -s worn. I don't know if the bad u-joint(s) are causing the vibration or not, but having seen how bad the middle one is, I'm a bit scared driving. So those two will get replaced. It would be nice if this fixes the vibration problem too.

Still don't know how to assess the carrier bearing, or what the significance is of the play that exists in front of the front u-joint.

RE: vibration, possibly u-joint
 

might need to get youre drive shaft balanced

RE: vibration, possibly u-joint
 

Is the vibration in the steering wheel or in the seat?

If its comming from the steering wheel then it is up front, otherwise its in the rear.

Could be:
1. Out of balance
2. Bent wheel
3. Broken belt in tire
4. Bad balance (If done incorrectly, it can still be "unbalanced")
5. Out of alignment
6. Feathered or cupped tire tread
7. Brakes hanging up
8. Bad shocks or steering/suspension components.

Most tire places just throw it on and balance it real quick. Make sure the tire guy sets the machine up before balanceing. Makes sure he uses the correct measurements and makes sure he is taking the time to place the weights on correctly.

If you still have a vibration and you have identified the problem tire or tires.
A. Have them pull the tire off the wheel and place it 180 degrees from its original position and rebalance.
B. Have alignment checked.
C. Makes sure there are no bumps or valleys on the tread of the tire due to alignment wear or worn parts.

RE: vibration, possibly u-joint
 

Your problem sounds exactly like a worn U-joint. Even if there is no motion in the drive shaft (fore and aft play or left to right), they could be dry and when there is no grease, they fight the driveshaft. One lobe is probably bad and each revolution under engine load you can feel the lobe fighting the turning of the drive shaft. If you can't find the problem U-joint then replace the rear-most u-joint first as this is usually the most troublesome u-joint on trucks.

RE: vibration, possibly u-joint
 

My ujoint had the bearings out and practically was running running metal to metal. All it did was make a loud noise on the take off before I changed them, with no vibration. If its in the front you might want to check your motor mounts. That tends to create a lot of vibration.

RE: vibration, possibly u-joint
 

True, or a transmission mount. My 91' shook alot when my rearmost U-joint went bad.

RE: vibration, possibly u-joint
 

04BLKCHEVY - I think I have the same issue you described above. Did you just change the rear u joint or did you change them all? How hard is it?

RE: vibration, possibly u-joint
 

Removing the driveshaft was nothing, removing the u-joint caps from the drive shaft was a bitch!

Removing the rearmost u-joint:

1. Unbolt the clamps (i guess you could call them that) on the rearmost u-joint.
2. Swing it to the side and pull it out from the transfer case. Some fluid might spill from the case.
3. Now you have to remove the clips and hammer the caps out of the shaft (uh huh huh huh, he said shaft) You need a piece of bar or a heavy duty socket or something to stick in the hole to prevent you from beating the sh*t out of the drive shaft.
4. Once you have it pushed though you need to finangle the damn thing to get the caps off and to wiggle it out from the holes. It took some patience on my truck but it wasn't too bad.
5. Install reverse of how it came apart basically.

Note: I had to use the caps from the old u-joint to hammer back into the holes as the new ones would require too much hammering to get them in. The u-joint I bought has a zerk fitting and I think that might have something to do with why the fit was so tight. The caps for the one with the zerk were slightly different from the ones without but the clips and other dimentions were the same. The other two caps fit in the clamps perfectly when I reinstalled the drive shaft.

RE: vibration, possibly u-joint
 

Not to hard. Just takes a little muscle. I just replaced all of them since i was going to remove the shaft from the rear.Jcbst12 describes it pretty well. The bearings in my u-joint were completely gone, but no vibration just a loud noise. You might want to check all ofyour mounts. Try to get some wd-40 in there like the day before to losen up those bolts easier.

RE: vibration, possibly u-joint
 

progress !

The middle of the 3 universal joints was the only u-joint that showed perceivable wear/movement. On inspection, 3 of its 4 cup bearings looked excellent. There were no needle bearings left in the 4th cup. On the rear u-joint, 2 cups seat in the rear yoke. In these, there was a groove near the cup lips. The grooves appeared to be meant for c-clips that would 1) hold the cross in the center of the rear yoke and 2) act as cup retainers during high rpm. Despite their absence, there did not seem to have been any movement of the cups or cross towards off-center, and it took a bit of force to dislodge those cups once the 2-bolt clamps were removed.

Replacing the middle u-joint and adding the two c-clips got rid of 95% of the vibration. There is still a bit of vibration that occurs between 40mph and 50mph. This is noticeable only in the steering wheel.

The ball joints and tie rods show very little wear. There might or might not be a bit of play in the driver side front wheel bearing.

RE: vibration, possibly u-joint
 

Thats cool im going to cange mine soonstarting to feel something.

RE: vibration, possibly u-joint
 

better early than late. without any bearings in that one cup, i'm sure the heat was cycling up and down on that lobe, not to mention major mechanical stresses. i doubt it was a safe condtion. i'm glad i caught it in time and that it also resolved most of the vibration. post back on your results. i'd be interested to know if your rear u-joint is missing the 2 c-clips too.

RE: vibration, possibly u-joint
 

Ill let you know but it might be awhile im working at least 84 hours a week last week I got 104 hrs. But the more hrs I work the faster I will get this job done and get back south.

RE: vibration, possibly u-joint
 

After you get the U-Joints situated, get the front tires balanced. Have the guy calibrate the balancer and set it up appropriately. (Look at the diagrams on the machine for the wheel type). Then have him balance them, they should get close. Id not, try rotating then fronts to the rear or have them break down the tire, rotate it 180 degreese, remount and rebalance it.

RE: vibration, possibly u-joint
 

more progress, kind of ....

In the very beginning, I had the tires balanced, rebalanced, rotated, derotated, ... It would change the vibrations somewhat, but did not reduce them.

The u-joint work described above resolved 90% of the vibrations.

The remaining 10% occurs between 40-50 mph window. The same vibrations occur regardless of: 1) clutch in/out, 2) foot on/off the gas, 3) gear. The vibrations are mostly felt in the steering wheel. If I lay my head back on the head rest, then I can feel vibrations in my head, plus my visual field shakes quite noticeably.

To address the 10%, yesterday I had the tires dismounted, then remounted. Front tires went on the rear rims and rear tires on the front rims. They stayed on the same sides. After the swap, when they were balancing the tires, one rear tire was fair wobbly. The other rear had a small amount, and the two fronts were excellent.

The mechanic said the rim was bent. The rims are the OEM steel/chrome rims that came with the truck, which I bought new. I have no idea how the rim became bent. The tires have 8 months and 8k miles on them. The vibrations started about two months go.

The 10% vibration is still there unchanged. I am thinking about getting the one rim straightened, but it is fairly expensive at $70. Any suggestions?

Before that, I may swap it out with the full-size spare tire to see if that helps.

RE: vibration, possibly u-joint
 

I they are stock rims it might be cheaper to get one from a junk yard. Im glad to hear you fond out what the problem is. You would think they would notice the rim being bent when they balanced them.

RE: vibration, possibly u-joint
 

Keep you eyes peeled for a new one or used one on craigslist and ebay. Don't pay to have it straightened, not worth it. I'd use that as a last resort. Put the bent wheel on the rear for now. You won't feel it as much.

RE: vibration, possibly u-joint
 

another progress note ...

Replacing the bent wheel with the (unbalanced) spare (spare rim, 10y old tire) eliminated most of the remaining 40-50 mph vibration.

The wheel straightening guy said the wheel was bent through the center. He gave it a quick work over for free. Then I took it to have it balanced. The wobble was still clearly visible on the machine, but only half as much or so. It balanced okay. It had balanced okay before the straightening too. Now, there is less 40-50mph vibration.

At this point, both front wheels are true. Both rear wheels have some wobble. There is still some (barely noticeable) vibration.

So i guess this means I'm in the market for 2 steel/chrome 16" OEM wheels, 1999 Silverado 1500 2WD.

RE: vibration, possibly u-joint
 

Hey heres a good deal I think


http://www.ls1truck.com/forums/sale-...07-wheels.html

RE: vibration, possibly u-joint
 

thanks. unfortunately my tires have rolled only 8k, and they are 16".