Rear Wheel/Axle Bearings

[gavin]

So I've been chasing down a vibe in my truck for quite some time.
I've eliminated: everything in the front drivetrain and u-joints.
About the only thing I haven't eliminated, is the rear axle's bearings.

If the axle bearings are bad, will it cause a vibration at any/all speeds? What about the pinion bearings?

There is basically no play in the rear axle shafts, except for the slight amount of in/out movement (which I know is normal due to c-clips).

Also, when spinning the rear tires by hand, I hear a bit of a clicking (on both sides, and definately coming from the axle/tubes not pinion). Does this sound like something that toasted axle/wheel bearings would cause?

 

[wood1]

Hmmm, clicking, I'm not sure. I would put the vehicle on a hoist, have someone run the vehicle at a resonable speed and use a mechanic's stethoscope, listening to each bearing.

 

[gavin]

no access to a hoist, unfortunately.
But I do have a stethoscope I could use, and plenty of wheel chocks and jack stands lol. And already have my front d-shaft removed (for other reasons). So I s'pose I could try that out this weekend.
although I do hear it clearly coming from the tire area (which could only be the bearing, or something with the brakes but I doubt that)

also, I completely removed all parts and pieces to the parking brake, so I know it's not causing any issues.

 

[wood1]

Sounds like it may be the bearing then. Does the sound change if you are turning one direction or the other? That's normally a wheel bearing as you probably already know. I'd still listen to it with the scope before opening up the rear end, if you do end up changing the bearing, you might as well change both axle seals. It's also a good excuse to change to synthetic if you haven't already.

Good luck, don't forget to update with how you make out.

 

[gavin]

I posted on a local 4x4 board, and was suggested the same thing.

While driving, the only thing I can hear is the "hum" from vibrations.

I do not know if the vibes I feel change any when making turns; I've never paid attention, but will (try) to pay attention to that on my drive home.

And I actually do already have synthetic; although, it's a couple years old and I've been meaning to replace it again with some Royal Purple, just haven't taken the time yet (which may be a good thing).

What are the chances of the axle shafts needing replaced also, if the bearings are bad? I know it depends on how much scarring/pits/etc are on the shaft, but are chances fairly high?

I'm almost positive it is the bearings, though, now that I think about it.
I had a set of 33's on it for probably close to a year; all 4 rims are out of round, so I could definately see that pooching up bearings (hell, I'm sure that's why I destroyed ~3 sets of front wheel bearings/hubs in ~8 months)

 

[JohnJ]

I have never heard of axle bearings making a clicking sound. Noting any change in volume during turns will give you a good clue though. Keeping in mind that I mostly work on street driven vehicles and not off road type trucks, what I see is that typically they go bad in one of two ways:

1) Pitting. This usually makes a scraping or grinding noise. It usually isn't necessary to replace the axle shaft unless there is significant pitting on the shaft also. You'll have to see the bearing to be sure.

2) Even wear. Usually the axle shaft will also be similarly worn and should be replaced. Often you will have excessive vertical play and the seal will be ruined.

Note that when replacement of the axle shaft is indicated, sometimes an "axle saver" bearing (I get them from NAPA) can be used to allow reuse of the axle shaft. The axle saver relocated the bearing to a different position on the shaft and might not last as long as a standard bearing. Also, I would not recommend use of the axle saver for vehicles commonly used for towing or offroad use.

A clicking noise might be from a worn pinion shaft or if you have a locker it might be a normal noise from your locker. If could also be something silly like rust in the brakes or a flake of rust inside the driveshaft. Then again, maybe something in the diff is just broken.

You just might be able to save yourself a lot of time by pulling the axles out and visually inspecting everything you see. This also gives you a chance to turn the carrier and pinion without turning the axles.

 

[ericautopart]

If it is a bearing you don't want to drive the truck until it's replaced. If you spin the bearing in the tube it will wear a groove in the tube causing an indentation. Now you'll need a complete rear end housing which can add up to big bucks. If you suspect it's an axle or bearing I'd just change it over (Cheap insurance). Especially on an explorer where the parts are so easy to get. I've got all of the stuff and I can probably get your out of this situation for less than 100 bucks in parts.

 

[gavin]

well, I think the vibe actually seemed to lighten up when making left-hand turns, and either no change or slightly worse when making right-hand turns.

and I apparently not hearing any humming from the vibes; musta been when I had my front d-shaft on and I just stopped paying attention to it, haha.

I'm gonna try and tackle this project this weekend. It looks easy enough and like I should be able to get it done in a couple hours. Just hoping I don't have to replace the shafts too.

 

[wood1]

It's also a good time to freshen up the traction loc clutches... and maybe jamb a couple extra in there to tighten it up.

Take pics when you have it apart. Hey, you could a how-to thread on axle bearings!

 

[gavin]

about a 3'ish hr job for somebody who's never done it before... not too shabby
only thing left is to fill 'er up with gear lube. Gonna do that in the morn so that the silicone has plenty of time to cure.

and I got plenty of pics, and plan on doin a writeup since there isn't one on here already

will also post a couple pics of my axle shafts.. the wear on 'em doesn't look bad, but I'm no expert or have any real experience with it.

gotta go eat first... I'm fungry.

 

[gavin]

driver's side:

passenger side:

does the amount of wear look okay to keep usin the shafts?

 

[gavin]

well I filled up the diff this morning and drove into town to return the slide-hammer I rented.

definately a MUCH better ride. Although there is still a bit of a vibe, but much less, and from what I've been told on the local board I also posted on, the wear on the axleshafts is bad enough they should get replaced; or I should have atleast got the axle-saver bearings.

But, so far so good.

 

[gavin]

well that fixed this vibe... but still got one floating around.

only with the front d-shaft in.

now, I doubt it can be the d-shaft. Long story short, I bought a replacement on ebay that had a single u-joint at either end. Unforunately, due to the angle of the d-shaft at the t-case (~5*), it was too high for a single joint. So, I took the shaft to a local shop and had it converted to double-cardan CV.

now... because the vibe/noise isn't there without the d-shaft, it can really only be 1 of 3 things. The front output shaft bearing on the t-case, the d-shaft (although I doubt it, it is still possible), or the pinion bearing.

am I correct in thinking this?

quick edit: why I am really pointing towards the t-case front output shaft bearing.... I'm on d-shaft #4. Other 3, cv-joint went bad and was driven on. More than once was driven on for quite a few miles (work, finding issue, etc). Then, when I got the ebay replacement, vibes due to excessive angle on u-joint at t-case. Causing strain on bearing? Correct thought here?
I am going to try and check it out this weekend; I have a mechanic's stethascope I'm gonna try and listen on the front of the t-case to see if I can hear any grinding, and at the diff if the t-case sounds okay.

 

[gavin]

well I think I have concluded that it is indeed the front output shaft.

when turning by hand, atleast 1 spot has a fairly loud metal-scraping-on-metal squeel.

since 4404's aren't plentiful up here, and cheapest one at a junkyard is just shy of $500, I bought a rebuild kit and a new chain.

I'll be rebuilding it Memorial Day weekend, since I'll have a 3-day weekend.

Will post a write-up afterwards.

 

[wood1]

Keep up the good work.

 

[gavin]

unfortunately I haven't gotten around to rebuilding my t-case yet.
ended up spending more time on my front-end on Sunday than I planned.

Saturday, I replaced the rear axle shafts and bearings again.
Well, it's been much better.

I also decided to spend >5hrs trying to replace the front axle shaft bearings. Well I only got the dri side done, and just replaced the seal on the pass. side as the bearing felt good, and there was no way in hell I was gonna get it out with the tools I had (almost need a blind-hole puller for that one).

When I got home from work today, I decided I need to reinstall my front driveshaft, so I don't (presumably) destroy the viscous coupler/clutch anymore than I already have.

While I was under there, I decided to check a few things.
Front and rear pinions feel good. I can't feel any up/down or side/side play.
Front output on t-case feels good. Again, can't feel any play (except a slight amnt of in/out, but that's cuz the output is held in with a c-clip of sorts).

But the rear output on the t-case; although it does feel good, I hear a "clicking" coming from it. This wouldn't be something that's normal, is it? Everytime I push up, there's a click. The volume of the "click" differs depending on the amount of pressure applied. Sound of a bad bearing?

Only other thing I noticed, which I'm sure is normal; I hold the slip shaft at the t-case, and the diff end of the d-shaft has a very slight amount of rotational movement. Normal, correct?
If I hold the diff end of the d-shaft, I cannot rotate the slip shaft at the t-case at all.
I do know I need to grease up the splines in the d-shaft; would that cause any kind of constant vibe?

I'm just trying to pin this down, so I don't keep replacing s$^@ I don't need to; and I really am getting tired of working on the junk, lol. And can't afford to take it to a shop.