91' pickup 4x4. I have been hunting down a noise in the axle for awhile now and have yet to figure it out. The noise only comes from the passenger side when the hubs are locked and it is a high pitch squealing noise. It is god awful loud even at under 15mph, and if I have to go over roadways in the winter where 4x4 is required the sound is unbearing. Plus, seems like when whatever it is fails, it is going to not be a fun time at any speed.

Note: The noise only is producible when the hub is locked. If I put the transfer case into 4wh or 4wL with the hub unlocked, there is no noise.

I have done the following, and not just because of this noise, but because it was time to do them.

• new driver side hub
• new wheel bearings
• new axles
• new brass inner and outer bushings.

I have read people stating that the brass bushings make some noise so I though it could be that, but it was happening with the old bushings and the new. Not change, so I feel like the pitch or frequency would have changed with the new bushings if that was the issue. The only thing I can think of it being is the Drive Axle Shaft Bearing. I have changed the diff fluid and there is no disco party of any concerning findings there, so I am not sure. Is the Drive axle shaft bearing a known fail point?

Thanks!

 

Can you put it up on jackstands and spin the front and hear this noise?

 

Spin the front while it is in 4X4 up on stands?

The noise is not immediate, even when I engage 4x4 and lock hubs then drive it around. It takes a minute or two before the noise starts back up and usually it happens when going down hill, not as much going up hills.

 

You said new driver side hub but the sound is on the passenger side? Locking hub or the hub that the wheel mounts to?

When in 4wd and the locking hub is unlocked, the front drive shaft, the front diff and the CV axles are spinning. Just not driving the wheel hub. It should still be spinning the inner gear of the locking hub as well.

So when you engage the locking hub, the outer gear splines to the inner gear to drive the wheel hub. If your wheel has been spinning down the road just fine, it sounds like your passenger side locking hub failed. I've had my hubs stick and not engage or disengage before. The grease was old and crusty. They didn't grind or screech though. Kind of sounds like the outer gear in the locking hub failed.

My best guess based on your information. Good luck with your truck!
Scott in AZ.

 

@aztoyman I replaced the riverside hub because the tension spring had broke in it. The noise is coming from the driver side (so it seems), and they are manual locking hubs. The passenger side hub when I took it apart functioned fine.

Apologies for delay in response, I was trying to capture a video of the noise. Here you can hear the noise as it starts and stops for no apparent reason.
Hopefully this helps some.

 

Man, that's a weird one. I've never heard anything like that. If it were in my garage now, I'd be putting it up on stands to listen and observe the tire and wheel with it going straight, turned both ways, hubs locked and unlocked, forward and reverse, if applying brakes change anything, and see if I could figure it out. Check for loose wheel bearings, bad CV axle. Make sure nothing is rubbing on the tire or wheel. Make sure wheel is on tight, see if anything going on with the brakes, Pull the locking hub off and see if there's a change. I'd be looking at everything. That would drive me nuts too.

 

Right! I cannot figure it out. Hitting the brakes sometimes stopes it, but I think only because it changes rotational speed. The only definitive factor is the noise only happens in 4x4 with the hubs locked. I can run it with the hubs unlocked in 4x4 hi or low and it does not happen.

The whole front end of the truck is fairly new. I redid it all maybe 2 years ago. Axles, tie rods, ball joints, shocks, rebuild the hubs with need bronze or whatever material those bushings are, new wheel bears.

One thing, I noticed is the sound happens more decelerating down a hill/incline vs going up. Also if I turn the truck tight to the left even in 2x4 and hit any type of up or downward slope the front end creaks/sounds like binding really bad. I can get some video/sound of that as well.

Are the axles different lengths? If so, would it be hard to mix match them? I forget since it was couple years now, but was one thing I was thinking of. Also, one side of the truck at the end of the axle has the C clip in the hub housing the other side does not. Not sure how big of a factor that is.

I will start digging into the truck. I'll have other more jack stands to get all 4's off the ground so I can watch it rotate.

 

Here is the additional front end noise when in 2x4 and having the wheel turned all the way to the left.

 

On the second noise have you tried a little grease on the steering stop bolts? Not sure what the exact name is for them

 

I agree with Discombobulated on the 2nd noise. Hitting bumps when you're on the steering stops sounds horrible.

 

I will take a look at the doing some grease on the steer stops. Still waiting to get under the truck while it is up on jacks. Need to not be alone when I do that....just in case ha.

 

On the second noise have you tried a little grease on the steering stop bolts? Not sure what the exact name is for them

 

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