The Axel vent is generally on the driver side of the axle and has a hose running up to the inside frame near the drivers side tire, i'm not for sure where it is on the EX but if the oil is getting very hot and smoking that's where the smoke will exit.

 

A bad differential carrier bearing would sound veary similar to a bad wheel bearing, A Pinion bearing will sound much faster sounding then wheel bearing and generally change pitch with driveline load.

 

Went for a 12 mile drive at an average speed of 45mph, limited stop and go. Ambient temperature is 35 degrees. Here are the temperatures

Drivers Hub 62
Passenger Hub 63
Rear Center Diff 96
Rear Driver Side Diff 126
Rear Passenger Diff 95
Rear tube out to drivers wheel - ranged from 70 to 50 then increased to 80 as I reached the rotor
Rear tube out to passenger wheel - ranged from 60 to 40 then increased to 80 as I reached the rotor
Front of differential near pinion - 89
Both rear calipers - 72-75

The one in bold seems to be the odd ball out.

 

My best suggestion would be to ask Christina but I don't think she knows...

 

Looks like you found the problem!
Just remember, all of the filings/pieces from that thrust washer or carrier shim that you found are still in there and going through all of the bearings, hub bearings, pinion bearings, carrier bearings, the more you drive it the more damage you are going to do to everything in there!
If I remember correctly you did something with that diff a few years ago!
I think you are going in there again.

 

Has no one mentioned the teeth marks in the carrier from the pinion gear? Are those from a previous incident or are they new?

Time for a rebuild.

 

You had it stripped down already, four bolts and you would of had the carrier out and could of had a look at the bearings! Haha. I would say the side bearings are shot by your temp readings. Time for a rebuild. It's been a while since I rebuilt a sterling but I don't remember them being difficult . Good luck.

 

Sorry to get off topic, but does anyone else see the optical illusion in this pic. It's the first thing I noticed. The best kind are the ones not rigged.

 

Well I think it's highly unlikely a trust washer/shim went bad. They are between the race and the housing on that carrier. But that doesn't mean the bearing isn't bad.

If you pull the axle shafts, than the 4 bolts on the bearing caps. Be careful, as if the bearings are shot, that carrier is basically going to want to fall right out after the last cap is pulled off. Usually they should be nice and snug. A set of pry bars, and it should slide out without too much issue. Make sure you keep the bearing caps, shims and races separate for what side they came off of.

 

Took me a minute but I definitely see it. Haha. It's the Chris Angel of Excursions.

 

Yes those are old and the gears were replaced after whatever caused those....well that was the conclusion we came too - this is a used axle that I put in this truck - so don't have a real history on it. Starting to wonder if it was "fixed" properly the first time.

 

Oh Dave I'm not that brave! If I have to replace a bearing in this thing it's getting new gears anyway so not sure I'm going to unbolt the carrier. I may need to start looking for a gear guy - guessing this is one where Ford is going to be my best bet.

 

Too bad your so far away, I'd drop the carrier out for you just so I could see what's wrong with it!

 

I hope you can find a good gear shop. Ford will probably want to sell and install you a re-manufactured drum to drum rear end. +/- $3000.00+install

FYI...A complete rear(backing plate to backing plate) at Rock auto is $2323.79+core+shipping+shipping the core back to them.

Good Luck!!!

 

I would check for a used unit, start at car-part.com, rear ends usually do not give too much trouble.