Should I be greasing my U joints?

You might be surprised after 50 years those greaseable U-Joints could be going bad, flat spotting the cross shafts.

You can take the rear U-joint off the rear end and work it by hand and see if you can feel any roughness. Then carefully pull off one of the bearing caps and check the crossshaft for indents from the roller bearings.

Same with the front yoke. Pull it out of the tranny and run it through the motions to feel for roughness.

Not that bad to just replace them, then you know they are good.