Rear bearing seized onto rear axle @ 177k miles

[Ben Rumson]

Without notice my right rear axle bearing went out. No pre-grinding or warning what so ever!





I was in town driving 30 mph when it went out - horrible grinding (metal on metal) sound from the rear end. I pulled the outer hub cap and could feel the heat on the axle hub.



I limped it home - 8 miles. By then it had virtually welded itself to the threaded axle housing. As a result, I had to CAREFULLY torch cut it out from between the inner threaded axle and the hub housing on the outside. The bearing didn't budge until all bearings had been cut loose. It was a 7 hour job to get everything apart. The hub housing could NOT be pulled off. It had to be torched.



It was scary as heck torching the bearing and race off. One wrong move and I would have dammaged either the lug nut housing (outside) or the ENTIRE axle housing (inside) - because the axle on my rig is all ONE piece. The threaded inner axle shaft is PART OF the rear axle housing.



The 2 1/2 inch outer axle nut with nylon imbeded in the top had all the nylon melted away and the trough-shaped retaining pin was fried as well. These were fried before I had to get in there with the torch.



The new bearings and seal cost $30, BUT the new 2 1/2 " nut and retaining pin (Dealer only parts here) was $50!! I could have replaced BOTH sides (bearings and seals) for the cost of the fried nut alone.



I'm dang lucky I wasn't hauling a load back from Montana and in the middle of BFE.



My advise to all is to replace your rear axle bearing on your preventive maintenance schedule (every 80K to 100K - depending on how hard you haul) and DON'T wait till they go out on their own. It will be MUCH cheaper and safer to do them on YOUR time and place.



And... they're not hard to replace - 30 min. job IF they're not seized and welded to your truck.

 

[Philip]

I pulled the outer hub cap and could feel the heat on the axle hub

This is the best way to check. If you go out on a drive for 20 miles or so. When you stop walk around and do a hub check for heat build up. If one hub is warmer than the opposite side. Something is wrong.



I do this anytime I am out driving. I drove OTR this is about a built in trait now.



BTW what is a hub cap? I pitch those things real fast after I buy something.

 

[rrausch]

Was your rear end low on gear oil? Was there any evidence of oil seal failure?



I've got 150,000 on my '95 and just did my 3rd set of axle seals, but the bearings themselves looked fine.

 

[Ben Rumson]

Response

Was your rear end low on gear oil? Was there any evidence of oil seal failure?

I've got 150,000 on my '95 and just did my 3rd set of axle seals, but the bearings themselves looked fine.

I also have replaced the rear axle seals once each. One at 140k (oil all over the break linings) and the other at 170k (small seapage of oil inside the break drum).



When the bearing seized there was no warning what so ever - period. Just a horrible grinding noise (and feel) all at once from the rear end.



I pulled over and felt the temperature of the rear hubs and differential. The right rear hub was notably hotter than the other hub and the differential. Just like Philip said.



I couldn't believe that just the bearing would make such a loud grinding noise... so I confirmed the hub and eliminated the differential by checking the differential oil level. The oil level was fine.



The oil seal was still intact when I torched the bearing out. Had the drum been pulled BEFORE the bearing went out, there would have been no noticable sign that it was ready to go. Pulling the drum will let you check for an oil seal leak, but the bearings would be very hard to check. You could maybe try and wabble the bottom of the tire in ward and outward while it was up on jacks to see if there was "any" slipage (like a worn ball joint), but I think even doing this would be hard to detect any problem with the bearings. If there was enough slippage to feel, by doing this, I would guess you'd already KNOW you had a bad bearing just by driving the truck. There should be no slippage inward and outward.



I don't know of a way to accurately check the bearings. Over time, I guess, one bearing could run a little hotter than the other and lead you to know that it's getting ready to go out. You'd have to check them enough to know what's normal temp and what's not - like Phillp does. But even then, it might give up the ghost from one mile to the next.



You just never know, for sure, when they decide that they've had enough. If you have 150k (which is commendable) you're going to have them go out SOONER than later. Spend $60 and buy 4 bearings and 2 seals and replace them (at YOUR leisure - not it's) and you won't have to wonder.



Who cares if they go 170k or 150k? Braging rights on how long a part lasted is one thing, but you have decent mileage out of them now. It would be wiser to say that you replaced them before there was a problem than to say you got 20k more out of them... but it ruined everything else with it, leaving you in the back 40, and it cost several hundred dollars more to fix than if you had PM'ed them at 150k.



At 150k (IMO), you're on borrowed time. As far as preventive maint. goes, $60 is nothing - especially compared to what you could be looking at if they go out on you while you're on the road.



Replacement is straight forward. PM me if you have any ? or need help.

Good luck.

- Ben



Please, spend the money and forget the unknown

 

[rrausch]

Thanks Ben. Good advice. I'll pick up a set and do them the next time I have some spare time.

 

[Hohn]

This is one of the reasons that I overfill the rear diff by a small amount. It goes a long way towards making sure that the seals have all the lube they need. I know that doesn't help the bearings much in this case, but...



I strongly second what Ben Rumson said. Bearings are a cheap and easy preventive maintenance. I'd do them every 100K at the latest.



Oh-- and be sure you use Timkens



jlh

 

[rrausch]

You don't know the numbers for them do you?

 

[drrhoades]

OVerfilling the diff can lead to the hub seals blowing out. It is recommended in the service manual to fill to . 75" under the fill plug on the rear axle. Overfilling can cause foaming and cause the housing to pressurize.

 

[Hohn]

Excessive overfilling CAN cause problems, albeit not commonly.



But a slight overfilling is even safer than slightly overfilling the engine crankcase.



I use a synthetic lube that doesn't foam.



I'd also like someone to explain to me exactly how that axle housing can become pressurized when either 1) there's a vent to equalize pressure, or 2) it's sealed, thus no air can get in! Is it just from the heat of the ring and pinion?



Anyway, I've seen a LOT more failure from underfilled axle with dry seals than from overfilled ones. I've had good luck with it, and there's no plan to change any time soon.



Justin

 

[nickleinonen]

Overfilling can cause foaming and cause the housing to pressurize.

the diff has a vent hose coming off the top of it to keep it from pressurizing...

 

[Ben Rumson]

You don't know the numbers for them do you?

Yes... and No. The numbers depend on your exact truck - not just the year, make, model.



Example: My truck is a 95, but has a late 94 Dana 70 axle. I didn't know this when I bought the parts initially.



When the parts store looked up the part numbers using my year, make and model, they sent me home with the same diameter inner and outer bearing. However, my truck actually has a larger inner bearing and I had to ask my lovely wife to run back to the store to exchange it for a larger one.



Findings: My truck has a larger inner bearing and a smaller outer bearing. Some 95 trucks (according to the parts store's computer) have both bearings the same (smaller) size as the outer bearing.



In my case: My larger, inner bearing is a Timken #28682 (Very heavy and well made). Plus on outer Bearing Race to match the #28682. 2 pieces make up the inner bearing assembly: the Race and the Bearing.



The smaller, outer beariing is a Timken #6408. Plus an outer race to match it.

2 pieces make up the outer bearing assembly as well: the Race and the Bearing.



The oil seal is a part number #417158.



In my case, the outer diameter of the oil seal is the same diameter as the larger inner bearing - they go right next to each other.



Each side cost me about $30. This included 1 inner race, 1 inner bearing AND 1 outer race, 1 outer bearing AND 1 oil seal - 5 pieces per side.



If in doubt, I'd buy both sizes of inner bearing and then return the size you don't use. It may save your lovely wife (or you with grease up to your elbows) a trip to town.



Good luck with your Prev. Maint.

- Ben

 

[Cooker]

BUT the new 2 1/2 " nut and retaining pin (Dealer only parts here) was $50!!

FWIW for the others reading this thread - These are not dealer only parts. NAPA has them, the one near me has them on the shelf, or can get them for you at cost less than $50. Good luck having the parts guy trying to figure out what you need if they are not on the shelf



If you are not in need of the parts ASAP you can also order them at a reasonable cost from www.quad4x4.com



Also typically they are 2 9/16" but a special Dana Axle Nut Socket is needed to remove them.

 

[rrausch]

Thanks Ben, mine is the same as your--a '95 with early '94 Dana 70. I remember than one bearing is larger than the other. Thanks!

 

[jimk]

The oil level was lowered to help warrenty on leaking seals but is not good for the bearings or that is what is told to me. I for sure would not reuse the nylock nut unless you do something to keep the nut from backing off, as the factory locking device that is used to keep the nut from moving is cheap piece of metal. I was told that I can also go back to the old style of double locking nuts and plate. If you wipe out the end of axle housing all is not lost but it is not shade tree mechanics to repair.

My father made a jig that is used to center on the housing and hold a new stub end and weld it on. I have done this before and is done so on bigger trucks as well.

The welds are the same as if you are testing for x ray . 6010 or 7010 root and 7018 fill and cap. Tig can be used, not wire...

I would have to agree about replacing the rear bearings at some point as when you are down and on the side of the road in no where ville that is not good. jimk

 

[Shelby Griggs]

While replacing the bearings might be good PM, I have to believe that bearings failing is pretty uncommon, as I haven't heard of many failures here. I have 250K on my Grand Am, never touched the bearings. I would think with adequate gear lube with regular changes that our bearings would go just about forever.



SHG

 

[CumminsPower98]

I have to agree with Shelby Griggs. I have worked on many Dana axles many of which have hundreds of thousands of miles on them and the bearings are fine. I would have to say that either the oil level was low and the bearing went dry or it was defective or damaged from something else. That's fine if people want to replace their bearings but I don't know it's needed in most cases if you take care of your ride. I personally fill my axle to the plug if not a little more and have no problems. Oil bath bearings like this will go a LONG time. Look at all the big rigs that are run this way, I bet they don't get changed every 100k.

 

[Ben Rumson]

... These are not dealer only parts. NAPA has them, the one near me has them on the shelf, or can get them for you at cost less than $50.



... also order them at a reasonable cost from www.quad4x4.com



Also typically they are 2 9/16" but a special Dana Axle Nut Socket is needed to remove them.

Dang. I'm a day late and a dollar short again. I should have looked around a bit more for a better price. Thanks for the references.



Also, for the Axle Nut Socket, I use a thin-walled 2 1/2" socket - AZone for around $7. I then shaved off a slight amount from the inner edge so that it fits over the nut. It's a tight fit, but it has worked well.

 

[drrhoades]

The axle can pressurize if the vent becomes clogged. The pressure would be an effect of the heat from the gears and limited slip (if you have one and are using it).

 

[fj40charles]

I've overfilled my diffs ever since the first gear oil change. . I've got over 80K miles without any issues. I'm willing to bet the vast majority of bearing failures are on the driver side because of the crown of the road. If you have a vent and it is not clogged it should be fine. I run synthetic gear oil in my diffs. I just don't buy the argument that you need to swap the bearing out every 100K miles unless you're always towing something real heavy.

 

[Jetson]

I recall Mag-Hytek's thoughts on the Dana's was that the factory oil level was too low, barely above the bottom of the axle tube, so they designed their replacement covers to show the full level a little higher in the axle tube.