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Jumping the gun, I attempted to turn the engine of my 28 (60 years garaged). I soaked the piston tops in penatrating oil for a week, put the tranny in high gear, and turned the rear wheels. They both turned, convinced that I had turned the engine, I went on to other projects. I then had the unnerving feeling, that this was just too easy. I did the "test" again, and found that when in neutral, the drive shaft spins, in gear, the wheels spin, but the drive shaft does not. When in neutral, I can stop the drive shaft manually. It feels smooth, like this is intentional. As soon as I release the shaft, it resumes spinning with the wheel. I opened the dif, and found no obvious bits in the bottom, although bone dry.I am completely confused by this. If the rear was broken, either neutral would not act this way, or certainly not be so smooth? At this point, I have given up on turning the motor, as it would likely just do further damage, I will get back to it later, as I am doing a complete frame off job, but I just don't understand what is happening

Exactly how are you turning the rear wheels? It sounds like you have the rear wheels off the ground.

jack stands under axle

Sounds like your differential is doing exactly what it's supposed to do.

that's what it "feels' like, but if the drive shaft doesn't turn, but the wheels do, wouldn't the inverse also be true, and, well, bad?

Is there a clutch in the dif?

I bet both wheels turn in opposite directions!

Put the car on the ground and rock on the car back and forth. I bet you will then see the shaft move.

Ray - inside the rear axe housing is the ring gear and its pinion on the end of the drive shaft. The ring gear is mounted on a case that contains "spider gears" which are interposed between mating bevel "Axle gears" on the inner ends of each axle.

When you have the wheels off the ground and the drive shaft stationary, it is NORMAL to be able to turn one wheel freely while the other wheel just as freely turns the other way.

The reason for this is in turning one axle gear in a case that cannot move due to stationary drive shaft, the one turning axle gear turns the spider gears which rotate the OTHER axle gear in the opposite direction.

Purely normal in an "open" (not limited slip) differential.

John Oder

quite humbling, but thanks all!!

Ray,

Ray, no worries, I asked the exact same question about a year ago before I understood exactly how the differential worked. We are all here to learn new things!