Axle or Bearing Issue?

[mightykp]

1995 f-350 Dually, automatic. Towing with a car dolly when... sudden noise from rear left tire area. Truck stops to point where I think it's a tranny problem. Get out and check the wheels and feel for heat.
All seems okay. Nothing wrong with tow dolly.
Resume driving at low speeds and seems to be a thump. Also, now and again I think I hear noise on the left frame? Quick clank. Maybe 3 times in 300 miles.
Background: Recently replaced wheel seals and rear drums and shoes. Bearings good. Retightened, backed off a hair the spindle nut. Tires spin freeely. Added gear oil to pumpkin, tilted both sides to get oil down.
BTW not a Dana. No problem for the first 300 miles to car and first 70 miles with tow. Constant thumping even after the event. Another harsh noise from left side 100 miles from home.
Got her home. Jacked her up and tested for bearing looseness. Left side with issue tight. Opposite side a bit of play.
Here's the key clue: both dually tires on problem side have a flat spot. Melted.
Any ideas?
(and yes this is a powerstroke but highest sage advice resides in these chambers)

 

[Rdnck84_03]

Since it is drum brakes, I am going to guess something came apart in the brake on that side.

James

 

[mightykp]

No oil or issues with bearings or brakes.
Dropping the differential cover and inspecting.
Could a chipped tooth have locked the driver side, causing the skid and flattened tires?
Will post a pic of pumpkin.
Still have no clue where to look.

 

[mightykp]

Major gear grinding...
How to fix this?
And what's the cause?
Pic is looking up and toward front of truck.

 

[Rdnck84_03]

Pinion bearings are bad or the Pinion nut is loose allowing Pinion to pull backwards into carrier.

James

 

[mightykp]

Disconnected driveshaft and removed front bearing. Great Shape.
The nut connecting the bolt to Yoke/pinion running back to gears was tight.
Remove rear axles and check the inner bearing?
Does that bearing just fail and shift rearward?

 

[u2slow]

IMHO, better check the pinion again.... take it apart.

But before you do that.... Take a prybar and see if you can force the carrier left or right in the housing. If it moves noticably, the carrier bearings are shot.