My father purchased an 2wd 5050 new, perhaps in 1977. The tractor has approximately 2200 hours. Never had a loader. I wouldn't call it's work all light duty, but it is mainly a mowing tractor. Tractor has been stored fairly well, had fluids attended and has been dependable except for a lift pump and an injector pump.

We have a new rattle and stiffness in the rear. When cold if you jack up either rear wheel you can not spin it by hand. Once you have started and run the tractor a few minutes you can turn either wheel by hand , but just. It seems the sides are symmetrical. It feels like a brake dragging, but it is not as I have both backed them off and looked up at the bands as my father rolled the wheel back and forth to see if they move, they do not.

It seems that it is in the differential or the output side on the transmission. Of note we did run the tractor a few hours down a little less than two gallons of hy-trans fluid. This included some steep up hill and down hill travel.

NEXT:

• Sounds seem to telegraph around this tractor, so I have not been confident I can narrow it down. We are going to try rolling the wheels while the tractor is off the ground while listening using a stethoscope.
• Jack up both wheels and see if the issue continues if/as both wheel are spun (this test with the wheels on the ground resulted in continued noise.
  
• I will also do some tight turns to see if the diff complains.
• I will drop the oil and see if there are any chunks.
  

Suggestions?

For some reason I am leaning toward the damage being in the output side of the trans rather than the differential.