I had the ball joints and shock replaced on the passenger side front axle about 8 months ago. I was getting an occasional vibration after but I never did anything about it. This morning after I unlocked my hubs, I got a really bad vibration. I looked under the truck and it seems that the outer axle shaft knuckle is hitting the top of the lower ball joint. But it only happens when the hub is unlocked, it seems that when the hub is locked it somehow helps keep the axle in place. If someone could shed some light on what keeps the outer axle from shaking up and down it would be greatly appreciated.

Thanks!

 

The axle should be held mostly in place by the needle bearing in the hub and the bearing in the lockout. If it's flopping around, you should take it apart and see what's broken.

A good place to start is here: Welcome to guzzle's 4x4 Needle Bearing Maintenance Web Page

 

Yeah, I've read Guzzle's stuff before. But what I don't understand is why it flops around more when the axle is unlocked? It's still being held by the same bearing.

 

When the hub locks, it slides the collar closer to the u-joint, giving the bearing better leverage to hold it in place.

 

Interesting. I wasn't aware that was how it worked. I hope I didn't trash auto hub. If I remove the auto hub, how much play should there be on the axle? I've checked before and there is more play on the passenger side then the driver side but I always attributed that to the iner axle shaft being way longer on the passenger side hence giving it more ability to move up and down.

 

It's hard to say how much is too much, but you definitely have something going on.

 

Time for some Timkens....You need a unit bearing or two from the sound of your problem coupled with my own experience.

 

I agree with Mike. When the Unit bearings on these go, the angle of that stub shaft can change to make it hit the lower ball joint. Depending on what kind of tires you run, it is not uncommon to mistake the hum of a bearing on the way out for tire noise. I would jack up each front corner and with a helper, use a long lever to pry up under the wheel while watching for movement in there. That should help narrow it down if it is a bearing that far gone.

 

I should have answered your question. There should be little to no play (up/down/side-to-side) in the u-joint on either side. When that u-joint wobbles, or it moves when you wiggle the tire (jacked up off the ground), your unit bearing is suspect. With as much play as you are describing, it should be making quite a bit of noise going down the road. Walk next to the passenger wheel while someone slowly drives your X backwards and forwards in the street or driveway. You will likely hear it.

 

The u joint and both ball joints were replaced recently. What I'm referring to is when you pull off the auto lock hub, you can wiggle the outer axle shaft a bit. The driver side didn't move much at all but the passenger side has a bit too much play (or so I think). I'm pretty sure it's the unit bearing. Guess I'm going to order a Timken unit and wait for some warmer temps to change it.

Btw, before the ball joints we changed there was quite a lot of play, I think in the lower one, can't remember for sure though. I'm thinking that may have masked ant play in the unit bearing. I didn't check it personally after as my mechanic did the ball joints and it was off the lift by the time I got back to pick it up.

 

Does your ESOF still work? It's the time to fix it while you have it apart.

You also might have damaged the stub shaft, but you won't know until you get it apart. Just look at where the needle bearing rides and make sure there's no scoring.

Also if your lockouts don't turn easily, good time to fix that too. The link I gave you above also has a link to a page that explains how to disassemble, clean and lube them.

 

Yeah I've read through Guzzle's stuff many times in the past. He's got some great info. My ESOF works, occasionally one side won't unlock and there's a slight rattle in the auto hub. I've been planning to pull it apart and grease it up per his instructions but I haven't been able to make time for it. If I do the unit bearing myself I'll do the auto hub at the same time (there's a chance I'll be able to get my mechinac to do the labor for free). And replace the dust shields yet again....

 

New York loves its salt in the winter. When I took my truck and RV to visit my family everyone was shocked at how rust-free it is.

 

Haha....yeah. Thankfully this winter hasn't really been much so there hasn't been much salt out. And for some reason they barely salted before the last storm. Really could have helped, there's was a ton of icing Friday morning. I just try to get a car wash more frequently and after long road trips in the salty months. Works well enough for me.

 

If you strip it down pay close attention to the machined surface on the stub axle that the needle bearing rides on. It could add to the play in the axle if it's degraded.