Differential Questions

Drizzt · 01-31-2018, 05:23 PM

I have a 2003 E350 with a semi-float axle and ARB locker, and I'm differential deficient (have never had one apart so don't know $h!t). About 10K miles on the ARB install. Never a problem, has always worked without fail; been all over Texas, Colorado, New Mexico and Arizona with it. Recently the pinion seal started seeping a bit and being OCD I had a shop replace the seal and flange. Then the problems started.

On the first 20 mile hwy drive on the new seal, I swear I could now hear a new droning noise coming from the rear of the van but I have no way to confirm that. Later, I notice some oil dripping under the axle. Upon further inspection it's coming out the vent tube. Just to verify I moved the vent hose to a different location and it is definitely coming from there. Pulled the drain plug and the oil was just about at the level of the threads, which is always what I'd been told is the correct level. However, I noticed that the diff cover was pretty warm when I first went to pull the plug after the 20-mile drive home. I wish I had a temp probe to qualify "warm" but it was like holding a hot cup of coffee in a paper cup is how I'd compare it. Just seemed warm for a 20-ish mile drive. When I had the plug out I didn't notice any metal, but I will say I didn't give a real hard look but with a headlamp in the dark I would think they would have been obvious.

With a total of about 100 miles on the new seal, I take it back to the shop that installed it. After they look at it the first thing they ask me is if I drive on the hwy with the locker engaged. No, stupid, I don't. Found that to be an odd question for the problem being diagnosed. Then they tell me that when on the lift and the locker engaged there is a noise on the drivers side when turning the wheels. They also say there is metal on the drain plug. I asked if when they replace the seal if there is a bearing clearance they need to set that could have messed up the backlash in the pinion but they said that nothing they did would cause this problem and I really don't have a clue.

So, that all said, does it really sound logical that this is just a massive coincidence that they replace the seal and now it's suddenly puking oil due to a previously undiagnosed problem?

David

winmag4582001 · 01-31-2018, 05:44 PM

What kind of shop did the work? Was it a auto repair shop or an axel shop?
Here in Denver there are but a few shops that do good work. 95% of the places here I wouldn’t let touch my lawnmower.

If it was done at a reputable axle/gear shop, it may just be a coincidence.

I know I didn’t answer a dam thing. IMO find an axle shop to examine it. And stay away from chain stores.

carringb · 01-31-2018, 05:55 PM

Pinion seals on the Dana 60 don't often just fail. What probably happened was bearing wear, which initially caused the seal to go. When they put things back together, they almost certainly torqued the pinion nut to spec, but if the bearing had wear, re-torquing it without new shims means the backlash is too tight, and hence the extra hear. Hot Coffee is should be in the 150-180F range, which is way to hot after 20 minutes of driving. The tight backlash would certainly cause gear wear, which is the source of the shavings.

So no, not really a coincidence, however I wouldn't really fault them either since pre-load wouldn't wouldn't change if there was not bearing wear. Ford/Sterling axles in the pickups frequently do have leaky pinions seals (or did through about '04) and the cause really just is a bad seal. But with the Dana 60 and 70, more often than not, bad pinion seals are just a symptom of a pre-existing condition. Ditto for wheel seals on the semi-float version.

Really, the Dana 60 is pretty borderline for the 400+ ft-lbs of the torque the 7.3L makes. I broke mine not even 50,000 miles after buying the van, upgraded to Dana 70 internals then broke it two more times. Now I'm going full E450 this time around, post coming soon....

REF · 01-31-2018, 06:06 PM

Since I'm currently in the middle of having a FF built after I noticed my pinion leaking on my SF, I've gained a bit of insight into what most likely is going on with yours.
Bottom line is that once you notice oil leaking from your pinion, your bearings are most likely shot, which the shop should have known and replaced while it was pulled apart. Once the bearings start to go, they create a bit of vibration or "wobble", enough to allow oil to seep past the pinion seal. If the bearings are left unchecked once you start noticing any leak, things can go from bad to worse, the hard outer coating on the bearings are chewed away, exposing the softer metal, then they just shred. Thats possibly where the metal is coming from in your diff and the noise your hearing. At some point the breakdown of the bearings causes the pinion seal to puke your diff fluid all over the undercarriage. I would say you are in need of new bearings, and possibly a new shop.....Good luck!

EDIT:carringb beat me to the punch and as always has great insight

Drizzt · 01-31-2018, 07:06 PM

Damn. Not what I wanted to hear.

The shop is a repair/hotrod/custom diesel outfit. They've built some cool stuff and have mostly done decent work for me in the past, but I've had a few questionable quality moments with them as well (although some would say I have too high of expectations, depending on who you ask...). Finding a good shop is ridiculously hard, especially for a van as nobody wants to work on them. Don't even get me started on Ford service departments!

Backlash issues is what I initially suspected when I felt the cover, but they were adamant that replacing the pinion seal would have zero impact on that. There wouldn't be a way to check the backlash if they just replace the seal from the pinion end from what I can tell, would there? I know they didn't open the rear cover.

So can somebody educate me on the difference between full float and semi float? Or point me to a good resource on it. From what I understood the difference was another bearing on the axle, and for normal duty the FF wasn't really warranted, but what I'm reading above makes me question that. This is being built with the intention of an Alaska jaunt in a couple years, possibly PanAm if I can get my shit together. Maybe I should head back to the junk yard and pull that full floater I saw under an E350 about a month ago...

EDIT: Why would the noise get worse with the locker engaged?

REF · 01-31-2018, 07:51 PM

My rig managed 170K on my SF-including numerous trips wheeling out in Moab and other Utah adventures, several trips out to the west coast and pacific NW, a trip up to AK towing our trailer, a trip east to Nova Scotia towing the trailer, a Baja trip and towing our boat to/from Powell many times, all loaded up around 10K lbs. All without incident until the recent Baja trip when it started seeping. Some go longer, some don’t last nearly as long.
As you can see from the diagram, the SF axles each rely on a single bearing contact point. The FF axles are much more stout and allow for greater weight and load carrying abilities. Another failure that can happen with the SF if things aren’t addressed is that when the bearings go, they will score the axle shaft causing them to break.
I felt it was time to upgrade, especially since I was already looking at the cost associated with tearing into the SF and replacing bearings and seals. It’s certainly something that should be considered if you plan on keeping the rig for a while and intended uses, not saying you couldn’t get away with fixing and keeping your SF and it being perfectly fine, for a while at least.

Sent from my iPad using Tapatalk

JoeH · 01-31-2018, 07:56 PM

Rear Axle Semi-Floating and Full-Floating - Off-Road Magazine

carringb · 01-31-2018, 09:57 PM

Quote:

Originally Posted by Drizzt

Backlash issues is what I initially suspected when I felt the cover, but they were adamant that replacing the pinion seal would have zero impact on that. There wouldn't be a way to check the backlash if they just replace the seal from the pinion end from what I can tell, would there? I know they didn't open the rear cover.
~~~~
EDIT: Why would the noise get worse with the locker engaged?

The pinion seal work didn't cause the backlash issue. The worn bearing did. Its possible that taking out the slop when they installed the seal made it worse, but really, it's death was imminent anyways.

When mine went out on New Years, it went from mild vibration on decel, to vibration on hear accel, in about 120 miles. It went from vibrating, to launching the driveline and punching a gaping hole in the differential in about a half-mile.

By the time you had it on the rack and heard the extra noise from the locker, there was probably already consequential damage from metal circulating, and the locker probably change loading on the spider gears or carrier bearing just enough to add more noise.

If it makes you feel any better, my 5th differential (and 3rd axle) is being installed as we speak. Hopefully this one will last me to my next van...

GAR · 02-01-2018, 10:08 AM

I’ve had a Dynatrac ProRock44 with ARB airlocker in the Jeep for the past 100K miles, and it’s been a really dependable axle.

I’m thinking a Dynatrac ProRock 80 (rated to 11k #’s) would be a good choice for a 1-ton camper van. Anyone have a (ProRock80) in their van? Any problems, likes/dislikes?

ProRock 80 – Dynatrac Defense

Gar

ShuttlePilot · 02-01-2018, 10:58 AM

Quote:

Originally Posted by GAR

I’m thinking a Dynatrac ProRock 80 (rated to 11k #’s) would be a good choice for a 1-ton camper van. Anyone have a (ProRock80) in their van? Any problems, likes/dislikes?

Gar

I like that every person I know that has had a Dynatrac axle that was fully built by dynatrac has never had a problem.

I don't like that I've heard a fully built Prorock 60 or 80 is well north of 10k$ just sitting on the pallet. Anyone know if that is true?

-Eric