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Vibration/Driveshaft?

fandersoniv

New Member
Joined
Sep 3, 2018
Messages
7
Hey Guys,

Just bought an '04 Avvy 1500 about a month ago, and have been fixing a few things up on it (It needed shocks and U Joints pretty bad).

Before replacing the U joints, I had a slight vibration between 70-80 (haven't had it faster than 80).  I assumed replacing the factory (125xxx miles) U joints would solve the problem.  I heated the nylon out using oxy-acetylene, then whacked the caps out with a hammer.  I'm thinking maybe this wasn't the way to go, as now my vibration is a little worse.  I did reinstall the driveshaft in the exact same position it came out (marked with chalk on both ends).

The driveshaft itself is pretty rusty, but it doesn't appear to be missing any weights, and the new Moog U joints did fit in both ends perfectly (with C clips). 

Today, I put the truck on jackstands, and I tried using a couple of worm clamps to help balance the driveshaft (adjusted and adjusted for about an hour) to no avail, I can only slightly clear up the vibration in a certain position on the driveshaft (at 70+mph).

Local shop wants $125 to professionally balance the driveshaft, but given it's rust i'm not so sure it's worth it.  A new driveshaft is too pricey.  A Junkyard driveshaft I'm likely to run into the same rust or out of balance issue again anyhow. 

What's next?  Should I try to take the rear wheels off and run the axle up to speed without the tires to rule them out?  The tires are brand new, freshly mounted and balanced, but who knows.  Maybe swap the fronts and rears? I'm almost certain this vibration is in the driveshaft though.
 
I should clarify that I had a 1-1/8 socket supporting the 'bottom' side of each yoke as I beat the U joint caps out. I didn't just go wailing away with the backside of the shaft unsupported :p
 
Could be axle bearing
Tires/wheel out of balance (search Road Force BALANCE)
Tire/wheel out of round

Driveshaft blancing should be done off the truck so tranny and differential do not effect.
 
  Slop in the yoke at the trans, and rear dif.
 
there's a very small (almost barely noticeable) amount of play in the yoke on the transfer case.  I can slightly wiggle it in any direction, but the seal at the back isn't leaking anything.
 
WHat type of vibration are we talking?

if you had clear glass of water in cup holder and water up to top... would it spill out all over?
or a very teeny tiny ripple across top occurs?
OR something in between....


I mean could this be a tire bouncing up and down like basketball on the pavement
or
something so small you need scientific gear to measure
or something in between?

need some sort of description of magnitude of vibration.

do you feel in butt or on steering wheel?

99% of vibrations are from tires since they are the largest OD item spinning and the hardest to make balanced since they are cast rubber with steel belts inside and can get flat spots.

 
Just want to say thank you both so much for your time, I really appreciate it.

If I were to put a glass of water in the cupholder, I'd get a ripple across the top from about 70mph onward. 

First I took the driveshaft back out and noticed that the front joint (specifically the yoke part) was binding up just a bit.  I lightly tapped both sides of the yoke right under the caps, thinking that might loosen the caps just a bit (and it did, and movement is now butter smooth).  I lifted the rear end up off the ground and removed the tires, just spun the axle by itself up to 80mph.  Most of the vibration went away, so i'm assuming the rear wheels/tires are a bit out of balance (although oddly enough, the vibration did not move to the front when I moved the wheels there)

Anyhow, most of the vibration is cured now, but I do still get some which is unnerving.  While up on stands and at 70-80mph, I notice a slight rattling noise accompanying the vibration which seems like it's coming from the transfer case area.  The vibration is felt in the floorboard and seat.  It's not quite enough to shake the mirrors or make the cab reverberate, just enough to make me worry about burning up a bearing or a bushing while cruising at freeway speeds.

 
Well, vibration is still there. Sometimes it's more prominent than others. Took tires out of the equation and still have vibration from about 70mph and up. Had the driveshaft inspected and balanced at shaftmasters in Lincoln Park - vibration improved slightly but is still there.

I guess today I'll take the driveshaft completely out and run the transfer case up to 70-80mph in the driveway and see what happens. I'm fearing it's the rear end :(
 
I bought mine with a bent front yoke.  The transmission shop said they didn't expect that when they replaced the driveshaft...  Put your yokes on a lathe to rule that out.
 
I'm fairly certain that the yoke was attached to the driveshaft by way of the front U joint when they balanced it.  I could be wrong though, will call to clarify tomorrow.

Thanks!
 
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