This morning I replaced my OEM front drive shaft with a Tom Wood's custom shaft. The install seemed to go fine, and I greased both the new shaft and my rear shaft (on which I recently replaced the rotoflex). Did all this with a friend who's a much better mechanic than I am.

So on the way home, I got a new, very noticable vibration between 75 and 80 mph. The truck drives fine until I hit 75, and then a get a pretty strong vibration accelerating through 75-80; if I keep accelerating to 85 or 90, it's gone. If I coast and slow down, I get a similar, but not quite as strong vibration in that same range, 80 down to 75, and then I'm good again.

Any idea what could be causing this? I suppose it could unrelated to the drive shaft install, but it would be quite a coincidence.

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Also (and unrelated I think), I'm still getting a very faint clicking sound that sounds as though it's coming through the drive's side left vent. This has been apparent for a couple weeks. It's very faint, and I would think it had something to do with the AC (similar to sound of a bad fan or something), except that I hear it when the AC is completely off, and it also seems to be related to speed and acceleration--I get it when I'm accelerating or driving at 60 mph or more.

 

It could be that your new driveshaft needs to be balanced. Or your tires need rebalancing.

As far as the clicking noise in your HVAC, it could be a leaf stuck in the air intake under the hood and it blows around when you drive.

 

Forgive my ignorance...shouldn't the driveshaft come balanced? If not, how does one balance it?

 

Yes it should have come balanced, but you never know. Are all of your grease zerk's alighned? You want them oposite one another. When one is down the other is up.
I believe that all the front zerks can be on the same side, but then the back has to be the other way.
So if the fronts are on the bottom then the back ones have to be on top. If I remember right that is how my trk is.
A couple of ounces spinning at 10,000 rpm equals alot of weight.

 

Hmm...No, all four of mine are on the same side. Here's two pictures of what the shaft looks like with me lying under the vehicle shooting up at the shaft. Rear first, front second.

This is exactly how the shaft was shipped to me...should this be a concern?

-Andrew



[IMG]local://upfiles/7042/BA55C2DEDE194D108FE681A22F0E542F.jpg[/IMG]

[IMG]local://upfiles/7042/0A42636B47804E37A6400E79F346F015.jpg[/IMG]

 

I think that the cardon joint is fine.
But I would put the rear shaft oppisite of the front.
I have a DI so I dont have any cardon joints, but all three zerks on each shaft are on the same side, front u-joint, slip joint and back u-joint. Then the rear shaft is opposed to the front with all three zerks again being on the same side.
Makes it hard to grease them, one shaft is always up so I cant get my grease gun on them with out moving the trk.

 

Did it vibrate above 75 before the shaft swap? In one pic it looks like a balancing tab had been tack welded on, not that it means it was balanced right.

 

No, the vibration just started, after the shaft install this morning. I've communicated with Tom Wood by email already, and have been assured that 1) the zerks should all be on the same side and 2) the shaft was balanced when it shipped. I'll talk to them further on Monday. Still not sure what the source is...

 

"So on the way home, I got a new, very noticable vibration between 75 and 80 mph. The truck drives fine until I hit 75, and then a get a pretty strong vibration accelerating through 75-80; if I keep accelerating to 85 or 90, it's gone. If I coast and slow down, I get a similar, but not quite as strong vibration in that same range, 80 down to 75, and then I'm good again."

I am having the same exact problem. I recently replaced my ujoints and when i got it back in i had thesame vibration. I have yet to pull it back out and look. Let me know if you get it figured out, good luck!

 

mcneal, that's interesting that you're experiencing the exact same thing...I was supposed to talk to Tom Wood today (their service is amazing--he tried to call me over the weekend after I sent an email regarding the symptoms)...but...

On the way into work this morning I got into an accident. Slammed into a stopped vehicle on an on ramp, which jammed my ARB bumper up into the grill and buckled the hood. No injuries, thankfully, but kind of still in shock.

So my Disco is sitting on the lot of an auto body shop, and I will not be trouble-shooting the drive shaft issues any time soon. Let us know if you find a solution, though...