Axle of Evil at 40K

**rionapo** · 07-17-2016, 10:08 AM

Just had the pleasure of replacing my left rear axle after only 40k miles. (Pictures below.) I'd appreciate any comments as to what may have caused this damage and whether/how to approach Ford for a warranty claim. (I have a 100k extended warranty package on the vehicle.) The van is a SMBW 4x4 conversion with a stock Ford 4.10 limited slip XC2 axle. (At least, that's what the info sticker says but I wonder if that's what's really there given this early failure.)

Here's the good side of the axle:

And, the other side:

Thoughts? Comments?

Don

**BroncoHauler** · 07-17-2016, 10:19 AM

Looks like the bearing maybe welded itself to the axle shaft due to lack of lubrication?

Herb

pjpvi · 07-17-2016, 01:42 PM

Way back when, my SF axle almost completely failed from what I'm assuming was too much weight. Luckily I caught it in time and went FF and never looked back. A number of people here have swapped their SF for FF.

If you are over weight rating, Ford may decline warranty????? Just guessing, I really have no idea.

BajaSportsmobile · 07-17-2016, 04:30 PM

I'd say it was moisture intrusion and rust pitting while the van sat unused for a period of time. That pitting continues to erode from heat and friction and gets just like your axle. The wheel bearing was surely just as damaged and if it did not would have catastrophically failed.

Starts with water...

**rionapo** · 07-18-2016, 03:31 PM

Quote:

Originally Posted by BajaSportsmobile

I'd say it was moisture intrusion and rust pitting while the van sat unused for a period of time. That pitting continues to erode from heat and friction and gets just like your axle. The wheel bearing was surely just as damaged and if it did not would have catastrophically failed.

Starts with water...

Quote:

Originally Posted by BroncoHauler

Looks like the bearing maybe welded itself to the axle shaft due to lack of lubrication?

Herb

Thanks, guys. On the water front, the van doesn't sit longer than a few days and we don't do much water hereabouts anymore. We drive it regularly to keep vermin off balance; our experience is a vehicle left stationary for a week or so is a nesting site. However, it could get wet during ski season and might stay wet even if used regularly. Plus salt even if we don't use that much of it hereabouts. Likewise, mud can be a problem, especially last year when we had the wettest summer in a decade. I made multiple trips to the car wash just to get the goo out of the wheel wells and off the axles. This was a particular issue while we travelled and there were occasions when the mud was on the axle for days. The wheel bearings were headed south; that's what made us realize we had a problem, fortunately before disaster struck. However, in the couple of hundred miles it took to get home and some light driving the week of the 4th (the mechanic closes shop after Independence Day), the wuh-wuh-wuh sounds of the bearing/axle contact got significantly worse. The mechanic says the scoring was from the bearings.

The mechanic didn't say anything about lubrication -- I should ask him specifically -- but I had not repacked the wheel bearings and they needed it, front and rear. Don't know if that's the lubrication you mean; color me utterly ignorant on this topic. There is nothing in the Ford maintenance schedule about the rear bearings. It does call for packing the front ones at 60k. Likewise, nothing in SMB's materials about wheel bearings. They do call for inspection and lubrication of the front axle at 30k, which I've done. Given my ignorance, I follow maintenance schedules pretty religiously. The mechanic says 30k should do the trick.

Quote:

Originally Posted by pjpvi

Way back when, my SF axle almost completely failed from what I'm assuming was too much weight. Luckily I caught it in time and went FF and never looked back. A number of people here have swapped their SF for FF.

If you are over weight rating, Ford may decline warranty????? Just guessing, I really have no idea.

We run around 6k on the back end, which is the rating, maybe a couple of hundred pounds more so I don't think that was it. But I do regret greatly not upgrading to FF just for the peace of mind.

Thanks for the thoughts.

Don

BajaSportsmobile · 07-18-2016, 10:14 PM

No rear wheel bearing "packing" as the bearings are lubricated with the rear axle gear oil. If that level is low the gear oil will not make it down the axle tubes to the bearings.

Semi Floating axle damage like you have is not uncommon, ask any axle shop that service van fleets. There is a lot of weight riding on that one little bearing contact point.

**rionapo** · 07-19-2016, 10:19 AM

Quote:

Originally Posted by BajaSportsmobile

No rear wheel bearing "packing" as the bearings are lubricated with the rear axle gear oil. If that level is low the gear oil will not make it down the axle tubes to the bearings.

Semi Floating axle damage like you have is not uncommon, ask any axle shop that service van fleets. There is a lot of weight riding on that one little bearing contact point.

That clarifies a lot. I didn't understand how the SF/FF option would play here since I'm not hugely overweight, if at all, and I thought it would be a more catastrophic type of damage. If I understand this correctly, low gear oil in the rear axle allows the bearings to come into contact with the axle. Since the semifloat axle is bearing (pun intended) vehicle weight, the wheel bearings are more likely to be pressed down into the axle, causing it to fail.

That helps me understand my mechanic's comments. He was convinced the axle was wrong and should have been a full float. However, he kept referring to the F350 equipment. My understanding is that the semi float is standard on the E350 so I didn't follow his argument -- though I would have been quite happy if Ford had installed the wrong axle.

JoeH · 07-19-2016, 05:58 PM

Don, the SF axle isn't really stock or anything it's just that the Dynatrac80 was an $8,000 upgrade from SMB. Some vans came with a FF from the factory, mainly those that were 15 passenger with a lot of glass. And even then by the mid-2000s Ford was mostly spec'ing the cheaper semi-floats anyway. IMO, it's the Achilles heal in the SMB 4x4 package given the weight of our vans.

Wheel spacers are also used to get the same WMS-WMS as the front Dynatrac60 axle and that puts the wheels even further from the bearing.

I just finished my conversion to a FF D60 this spring. I still have to use wheel spacers but it's not quite the same deal as with the SF. I sourced the D60 from a Phoenix salvage yard for $500. With new hub bearings, gears, and an ARB locker I'm into it for about $3k. The cat's meow is a D70 FF which has nearly the same width or is just a little wider with no need for spacers. They are hard to find.

Here's a couple of threads that I found useful when researching the issue and potential axle upgrades:
http://www.sportsmobileforum.com/for...-fun-6746.html
http://www.sportsmobileforum.com/for...ater-7175.html
http://www.sportsmobileforum.com/for...ide-12683.html
E350 Rear End - Diesel Forum - TheDieselStop.com
http://www.sportsmobileforum.com/for...ons-10051.html
http://www.sportsmobileforum.com/for...cers-1632.html

BajaSportsmobile · 07-19-2016, 06:51 PM

A couple of things may need clarifying...

First, E350s and E250s came with both FF and SF rear axles - SF being the most common.

SF has only one wheel bearing per side, they are out at the end of the axle housing, right next to the brakes (heat is no good...).

This bearing (pictured above) is a Cylindrical Roller Bearing that has no inner race, only an outer race that sits in the axle housing. The axle shaft has a hardened surface that acts as the inner race - that is where you showed the pitting and break down of the hardened surface.

The problem with low gear oil levels is the axle shaft needs lubrication where the roller bearings ride in it.

That single bearing carries all the load and so does the axle shaft, which also handles the torsional loads. The other end of the axle is supported by the differential carrier's bearings.

One thing to think about is that the axle is flexing around the "pivot point" of that single bearing -

little frightening to think about.

Worst case is the axle bearing surface and bearing start to fail and build up tremendous heat and then the axle breaks and the wheel and tire come off at speed, doing body damage or worse.

A few months ago, my partner Glen, was driving to the shop and saw a Sportsmobile, towing a boat, on the side of the Interstate - axle, wheel and tire had separated itself from the van - vacation buster.

Quote:

Originally Posted by rionapo

That clarifies a lot. I didn't understand how the SF/FF option would play here since I'm not hugely overweight, if at all, and I thought it would be a more catastrophic type of damage. If I understand this correctly, low gear oil in the rear axle allows the bearings to come into contact with the axle. Since the semifloat axle is bearing (pun intended) vehicle weight, the wheel bearings are more likely to be pressed down into the axle, causing it to fail.

That helps me understand my mechanic's comments. He was convinced the axle was wrong and should have been a full float. However, he kept referring to the F350 equipment. My understanding is that the semi float is standard on the E350 so I didn't follow his argument -- though I would have been quite happy if Ford had installed the wrong axle.

BajaSportsmobile · 07-19-2016, 06:54 PM

Shameless plug... now that I have put fear in your hearts, lol.

Agile has plenty of Dana 60 Full Floater Axles available to build to customers specs - choice of gear ratios and open or locking differentials with alloy axles with all new bearings and seals...

We also have a bunch of SF cores for things like good condition used axle shafts and differentials.