Ford SuperDuty locking hubs...

[WrenchMonkey]

Short version: Can I test-drive my truck with the locking hubs removed, and the axleshaft supported just by the unibearing?


Long version: I'm trying to track down a humming vibration in the front (Dana50) of my 2000 F250.

It sounds like a wheel bearing, hums from 20-30mph, but goes away after 3-4 miles. :confused:

But one wheel bearing is less than a year old, and the other has been replaced since the hum started, with no change. Pads, rotors, and tires have also been changed.

I'm beginning to suspect the locking hub. It's splined on the inside to accept the axle shaft, and splined on the outside to fit the unibearing ass'y, with a small roller bearing between the inner and outer halves. I think that bearing is the only thing left that rotates with the wheel, that I haven't replaced.

If I throw the 4x4 switch in the dash, so the axle shaft and the wheel will spin at about the same speed, the noise seems to go away. But it's sort of intermittant, so it's hard to say for sure. I took the one hub apart, greased it with Mobile 1, and I guess it got a little better for that first trip, but then started up again. Like I said, it's intermittant, so it's hard to say.

Before I throw more parts at it, I'd like to drive it around the block (or to work and back) with the hubs removed to check it that way.

There's another roller bearing on the inside of the unibearing that clearly is there to support the axleshaft, but I'm not if it's enough to drive on.


Anybody know?

Thanks!

Robert

[Hope Springs Hauler]

I beleive that is fine so long as you have the nut tightened to hold the unit bearing together

[JeffK5]

The unit bearing isn't serviceable..so it can't be loose. If the big ass nut on back is moving around don't drive it...had a hub assy. lock up on me going 40+ mph couple weeks ago , scary to say the least. I wouldn't drive it without a hub.. stub will shake like crazy.

I've put eight unit assemblies on my current 00 F350 PSD over the years...if I could do it again I'd ditch the D50 or at least the non-serviceable bearing hubs and go with the Dynatrac eliminator kit.

The noise description sounds like when my buddies 01 F250 lost a front pinion bearing.. turns out his front D-shaft turned more than he knew in 2wd.

[WrenchMonkey]

Well, it doesn't have a big hub nut, like my XJ does. The Ford just has a snap ring and three thrust washers.

No bigass nut on the back, either, so I guess I'm not sure what you're talking about there...

I doubt it's the pinion, I tried engaging the t-case again today and it definitely quieted down. I'd think a pinion bearing would get worse when driven.

I guess I've convinced myself it is the selectable hubs. Maybe I'll swap em left-for-right to check, before I drop the coin on new ones.

Hell, maybe I'll open em back up, and see if I can just change the bearing...

Thanks!

Robert

[hotrod]

just take off the snap ring and remove them, the hub is held on by the 4 studs on the back, should be ok for a short test
ive heard that the bearing packs are $400 each, hope thats not what it is, but like you said you can switch just about everything side to side to see

[itbrokeagain]

I know the PCV valves in the gas engines are good for making a humming sound when they go bad. Dont know about diesel though. Just a thought.

[Coppertop]

Robert,Have you tried getting all four wheels off the ground and running it in gear?

Humming sound,Sounds like a bearing.. Don't blame ya on not wanting to throw anymore parts at it till you know for sure.

I'm home sunday,will be in the garage till the game starts (4:15PM). Stop over ,I got enough jack stands to get her of the ground.

Your welcome to stay for the game.

Nick

Go Bengals! WHO-DEY!!!

[JeffK5]

The unit hub is held on with four studs.. the large "nut" I was referring to is the custom sized retainer on the back of the assembly that holds the stub spindle in.

Running it without the lockout isn't going to cause the wheel or unit hub to fall off... what could happen is the unsupported stub axle could flop around and destroy the needle bearings.

I attempted to drive my truck without a lockout and the stub went ..clunk..clunk..clunk ... not saying yours will do it also.

These front diffs are **** to start with , don't make it any worse!

Jeff

[WrenchMonkey]

ive heard that the bearing packs are $400 each, hope thats not what it is...

I paid $360 for the first wheel bearing I did, and $250 for the one last week. I've seen em online for $150. For the selectable hubs, Ford wants $330 EACH, Warn has a kit for $250 for the pair, and the off brand (MileMarker, I think) were $160.

Robert,Have you tried getting all four wheels off the ground and running it in gear? Stop over... Your welcome to stay for the game. Go Bengals! WHO-DEY!!!

I'd be stunned if it turned out to be the rear axle, and the noise is definitely with wheel speed, not engine speed.

Thanks for the invite, though! Who-dafawk-dey!

Running it without the lockout isn't going to cause the wheel or unit hub to fall off... what could happen is the unsupported stub axle could flop around and destroy the needle bearings.

That's what I'm worried about.


I'm gonna get the XJ back together first, then take the selector hubs apart and see if I can replace the roller bearing inside em.

Thanks all!

Robert

[JeffK5]

I just replaced both front bearing assemblies on mine in the last month, I paid $300 each ...Timken now offers them so I gave them a chance. I've ran everything from the ones that the dealership sells to Autozone,O'Rielies...they've all proven to be ****.