# if you know anything about driveline vibration at highway speeds, please chime in.



## monson770 (Dec 18, 2010)

i just replaced my u joints on my 02 2500hd, and it is vibrating in 4wd over about 45mph.. i am assuming that my u joints are installed crooked or my front wheel driveshaft is out of balance.. any comments/suggestions about where is should start 1st?


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## Philbilly2 (Aug 25, 2007)

when you pulled old u joints out, did you mark the shaft so that the short yoke is in the same spot as it was on the old u joint? if not, you might what to try flipping the short shaft 90 degrees.


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## 32vld (Feb 4, 2011)

Always mark the shafts so they go back in the same position.

But was this vibration there before or only after?

Did you actually see excessive play in the joints/driveshaft?

Is there a slip joint and does the slip joint have a grease fitting and did you lube the slip joint?


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## monson770 (Dec 18, 2010)

i did mark the yolks, on the front and rear shafts. lubed all u joints properly, and i'm fairly positive i installed the shafts back in correctly.. no slip joints to speak of..


i did mawr up the weight on the shaft a tiny bit when i had it in the vise, i'm not sure if thats enough to throw it out of whack? i'm talking about a 3-5mm sized gouge on the actual weight, not the shaft.. the only other thing i could think is, the shaft is flipped the wrong way(which i doubt but will double check), or, the jounts are installed crooked and are stiff or something...

not sure if just replacing the ujoints again will fix it if the shaft is out of balance, but i deffinately need to figure this out sooner rather than later.. anyone know where i take a driveshaft to get balanced?


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## monson770 (Dec 18, 2010)

32vld;1353027 said:


> Always mark the shafts so they go back in the same position.
> 
> But was this vibration there before or only after?
> 
> ...


my old ujoint was almost coming apart.. one of the four ends of the joint was sperated on the spline end of the shaft, needless to say there was play..


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## mossman381 (Nov 17, 2009)

I thought I read in one of my owners manuals that you are not suppose to go over 45 mph in 4wd. That might have been for my 98. Not sure why you would be going over 45 mph if you need 4wd.


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## monson770 (Dec 18, 2010)

my 4wd has always worked at any speed without issue, except now.. BTW i'm not driving around town in 4LO if youre wondering... i would imagine that it's easier on everything when doing highway speeds because, you are not turning as much, and especially on snowy roads.. I'm only in 4wd if there is snow on the road, if it's dry or even just a little wet, i keep it in 2wd. i don't ever go faster than about 55-60 in storms, but thats if i'm the only one on the road, otherwise i go as fast as i can without doing anything stupid!


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## Philbilly2 (Aug 25, 2007)

did you "set" the u joint once you put it in? What I am refering to is where you tap the yoke to get the u-joint set so that it moves totally free in all dirrections. Should not be tight at all, should flop around.


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## monson770 (Dec 18, 2010)

Philbilly2;1353986 said:


> did you "set" the u joint once you put it in? What I am refering to is where you tap the yoke to get the u-joint set so that it moves totally free in all dirrections. Should not be tight at all, should flop around.


No actually.. i noticed that one of the joints was tight, tbhus my reason for the suspision.. could a tight joint cause vibration?


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## Cosmic Charlie (Feb 1, 2009)

My 04 HD-2500 main rear drive shaft was cast iron (not Aluminum) and was very rusted and way out of balance (needed replacement) .. some years have different drive shaft materials ...


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## lilweeds (Aug 3, 2007)

monson770;1354486 said:


> No actually.. i noticed that one of the joints was tight, tbhus my reason for the suspision.. could a tight joint cause vibration?


Yes it will and wear it out quickly. I won't even do my own u-joints anymore. Look to see if there is a driveline shop in your area. The guy here will install and balance the shaft for like $150 including parts. Not worth the time for me to put them in.


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## monson770 (Dec 18, 2010)

ya i hear ya, i'm more of the, if i can do it, i'd like to type....

i had a feeling about that stiff joint, but after i got it all out and done it seemed easier to do it again... maybe the second time is the charm for me... hopefully!!!


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## monson770 (Dec 18, 2010)

Cosmic Charlie;1354506 said:


> My 04 HD-2500 main rear drive shaft was cast iron (not Aluminum) and was very rusted and way out of balance (needed replacement) .. some years have different drive shaft materials ...


i have seen the difference between mine, and my dads 04... major difference. the 2 only differences between our trucks may be the reason also though, he has the long box, i have the short box, and he has a newer model..


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