Denny, do you mean closed (torque tube) drive shaft U-joints? I have never heard of lubing exposed U-joints with gear oil. In fact, I have a '71 Dodge van that I bought new. It used to wear out U-joints regularly.
I contacted the Quaker State tech department and a lubrication engineer recommended synthetic grease. That was about 25 years ago and there has not been a U-joint failure since then using synthetic grease and relubing at 4000 mile intervals.
Maybe you could also "Ask the expert" on VCCA. He knows EVERYTHING!
Ray
