New axle shaft and now vibes, what gives???

I just converted my front passenger side axle shaft from a vacuum disconnect 2 piece to a non disconnect 1 piece and now I feel vibrations around 60mph and they lessen once I get to 70 mph. What gives? Is there some sort of support bushing that is supposed to be in between the differential and the hub bearing? I knocked the old one out because it was too small for the new shaft to go through. I also replaced the U joint in the axle before I put it in so I know it's not that. The only other thing I did was replace the ball joints in the drivers side which I doubt would make it vibe and before this work it drove fine with the 2 piece axle shaft. I'm pretty sure it's the 1 piece shaft wobbling around because I'm loosing gear oil out the passenger side axle tube and I just put a new seal in before the axle so it must have eaten that seal already. I did have the differential out but I'm pretty sure I got that back in correctly so that shouldn't have affected anything. Anyone have a guess as to why this is happening ?

TIA

A couple of ideas, worn axle U-joint on mine, would vibrate pretty good then stop (mostly) when I got above 70. I don´t trust the factory to lub my U-joint caps, I´ve had a couple over the years, that came dry or almost dry. I even had one, that had a little piece of paper in the box, about an inch square, that said the grease in the U-joint, was just a preservative and to be replaced with a high temp. grease before installation, I guess they saved a half a penny a U-joint with that one.
I´ve heard tell, the disconnect front drive shafts, aren´t balanced. Now that yours is spinning all the time, it might be the vibration. I´ve checked drive shafts before, with glue on wheel wieghts. To see if the vibration got better or worse. On rear driveshafts, changing the driveshaft angle, adding wieght to the rear of the vehicle, is a test for balalnce, kind of hard to do in the front.
They salt the roads here and pitted out of balalnce driveshafts, are fairly common.
The driveshaft U-joints are worth a look, the rear, front driveshaft, U-joint, requires a special grease gun end and is often neglected.

Well I just put a new U joint on the axle shaft that I swapped so I know that is good and I'm pretty sure the vibe is coming from that axle wobbling and not the driveshaft but I will double check it. I'm leaking gear oil pretty badly through the passenger side axle shaft seal that I just installed which is why I'm thinking it's the axle itself vibrating.

Front axles float quit a bit, a whole lot of play in them (at the diff end), they drive at the diff and align at the knuckle. A vibration is probable at the axle shaft , if for whatever reason, it has movement or play, off of the center line.
A bent axle is always a possiblility, a hub possible, though I´ve had hubs that were pretty darned loose, with no vibration problem, they kind of centered themselves. Doesn´t take much at the U-joint to, throw the whole works out of true.
Your vibe may be at another joint, that mostly just sat there, when you had the disconnect and and is now spinning all the time.
Might want to take a look at the front transfer bearing and for play in that yoke or the yoke at the diff. Though this would be pretty low on my list of probables, as the driveshaft for your disconnect axle, mostly just sat there, most of it´s life.
My best guess, would be something in the driveshaft.

I second the drive shaft as it was not spinning before unless you were driving 60mph in 4WD.

I'll third the driveshaft as the cause. Front shafts that come on non-vac D30's come balanced. Your's (if original) probably isn't balanced....either get it balanced or find a "new" one in the junkyard that is.
Jeff

The hub asseblies are actually only 4 months old, I learned the hard way that you need the axle stubs in them to maintain strength. The bent axle solution is all I can figure that would cause the seal to leak less than 20 miles after it was installed. What's the best way to test the driveshaft theory?? I'm thinking just removing it completely, any better ideas? Sticking weights on it sounds like a really hit or miss kinda thing and I have no idea where to even start to add weights.

Ok I got under the XJ today greased the font shaft and checked it for play, everything checked out fine. I'm pretty sure the shaft was factory balanced too, there were these little metal plates that looked like they were tack welded on there on both ends of the shaft, I'm guessing they are weights.

Of the 2 different size U-joints there are for the axle shafts how does the 297 differ, I know it's bigger but where? Cap? Body? The instructions on the tech article I read said that I needed to squeeze the caps back into the joint to get the clips in but I think I recall not having to do that and just pushing them in by hand. I'm thinking that maybe if the cap sizes are the same for the 2 U joints that I put the wrong one in by mistake since the salvage yard told me that the axle was from a '91.

AznDrgn said:

Ok I got under the XJ today greased the font shaft and checked it for play, everything checked out fine. I'm pretty sure the shaft was factory balanced too, there were these little metal plates that looked like they were tack welded on there on both ends of the shaft, I'm guessing they are weights.

Of the 2 different size U-joints there are for the axle shafts how does the 297 differ, I know it's bigger but where? Cap? Body? The instructions on the tech article I read said that I needed to squeeze the caps back into the joint to get the clips in but I think I recall not having to do that and just pushing them in by hand. I'm thinking that maybe if the cap sizes are the same for the 2 U joints that I put the wrong one in by mistake since the salvage yard told me that the axle was from a '91.

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I just done mine last week, had to press them out, but after cleaning the up I pushed them in by hand, I don't have any vibes.

I would like to know if the shaft you placed in there is machined to accept a seal at the shift motor housing. I ask because my 2000 shafts can only accept a seal in the first inch after the carrier, and no further. The rest of the shaft is too rough. Did your shaft have a mirror-like finish at the location you placed the seal?
Also, I looked up your seal and found it is
S:1.219, B:1.979, W:.406
What worries me is that I know my shafts are 1.195 inches in diameter at the seal location, and accept seals rated at 1.188. The shaft size of 1.219 is probably a tad too large, and the 1.979 might not be pressed in hard enough. Did the seal press in by hand, with a hammer, or did it require a tool?

I know this doesn't help with the wobble much, but it could explain the leak.

Axle wasn't machined at all because some other posters had told me that they installed many that way with no problems but I did take some time to smooth the section out with some fine sand paper not quite the same but better than nothing. The shaft is a bit thickers past the sealing point by the differential carrier so the larger seal actuall fits nicely on it. The seal didn't press in by hand but I ended up using the washer and all thread method shown in some of the tech articles I looked at, pretty much went in with the same difficulty that the original disconnect axle seal went in with. I've pretty much been convinced that the lack of machining at that point is what is causing the leak and I've been told that Warn sells a seal that fits the left hand side of the carrier since it isn't bored out like the right side. I just haven't had time to contact Warn and get one yet. As far as the vibes go I took off the front drive shaft today and ran some errands and it felt better but I won't really know til I put it on the highway and run it up to speed.

Well, here's another suggestion for the seal. I don't have the time this weekend to attempt an installation, but I picked it up and measure it to be 1.99 OD and 1.18 ID or so; it's National 473426. It has the spring loaded rubber seal too.

I went out in the shop and got down on my hands and kness and pulled out a dozen or so driveshafts (your welcome). The disco driveshaft I have has one wieght on the Carden end. The 242 shaft has wieghts on both ends, one on the shaft (near the Carden). one on the front yoke. Since yours has wieghts on both ends, guess it´s balanced. Wasn´t all a waste though, found some neat stuff I didin´t even know I had .
How is the over center preload in your Carden joint, there is a spring in there that (tries) won´t let it remain in the center position, it kind of wants to flop to the side (the way it´s designed).
My idea of slapping some wieghts on there and seeing what happens, is a classic example of linear thinking, I was thinking how I´ve done it, on some rear shafts before.
A good way to test the shaft (axle or drive) for true, is to get a rather large, thick stable piece of angle iron (cut to the right length) and laying the shaft in the V. Works for me.
If you dress a seal race, your supposed to polish it when your done, with like 800 grit Crocus cloth. Having it smooth, most ways, is more important than having it perfectly round, at least the way I was taught.

Finally got to take the Jeep up to speed yesterday without the front DS and what do you know there were no vibes at all so it was the driveshaft after all. Anyone know roughly what it costs to have mine balanced? and should I put new U-joints into it since it's out or would just greasing it be ok? None of them have any signs of wear or binding, 4wd was practically never used. If I do the u-joints should I do them before or after I get the shaft balanced?

As far as the seals go I called up Warn and the guy was nice enough to just give me the cross reference number to the seals that they use. So the one in the shift housing is a spicer number 46470, he said to just put it in and it should be fine but if I was worried about it sealing to take some emory paper to it and smooth the area out a bit. The inner seal just inside the differential carrier is a chicago rawhide number CR11343. He warned me to stay away from the national brand since supposedly they've had problems with them leaking. I've used national seals for years and never had a problem but I'm gonna listen to him this time since taking the front axle apart is a PITA and I've had to do it 4 times already for various things.