the drive shaft on my 1968 model 39 has grooves worn from the water pump seals. the machinists at work can rework it back into shape once i remove it from the LU. it seems like this might be a fairly simple process but the manual has me a worried. it is referring to lot of backlash and amount of play measurements that seem complicated. what i was hoping was that after i removed the water pump assembly i could pull out the prop shaft assembly, remove the pinion gear from drive shaft. drive shaft would lift out and i could have it machined and the reinstall would be a simple reversal of the tear down. i wouldn't pull any bearings that need special tools. if i keep track of all the shims and replace them correctly is this really that complicated of a job?