[rotorwrench]

The phantom spring in the clutch housing may be for the throw out hub return spring if it's a small coil spring. Larger busted coil could be from the pressure plate or disk if it has that type of disk.

When the transmission is in neutral with the clutch engaged, the input shaft and counter shaft cluster are all that turn. In any gear, the output shaft will turn. I would use the hand crank while someone watches the gearing. It's safer that way. If the rear of the car is up on stands with the spark plugs out, a person should be able to turn the whole drive system with the crank.

The U-joint is hard to see whether it's busted or not but it should make a lot of noise unless a shaft or yoke breaks clean across. The pinion gear on the drive shaft can also shear a key but it is equally hard to detect. The aft frame would have to be jacked up onto stands and the rear axle separated from the frame to get it out for inspection and testing. A busted rear axle will pull right out of the housing and the keys have already been inspected so at least that's done. The differential spider gear set it pretty tough so breakage is uncommon and generally will make a lot of noise if there is breakage. I've not seen a ring gear separate yet either.