Wendell,
There is an infinite number of amateur opinions on this subject and countless others. Those are humorous to read but of no other real value. The people who really know are the lubrication engineers at the various oil companies. They are enthusiastic gear heads themselves and want to help. All you have to do is ask. Here are some examples of questions I've asked them and got specific product information that hooked me up with the ":right stuff".
1. What gear lubricant available today has the same viscosity as SAE 160 recommended for the trans in my '36 Chevy pickup? (NO, it is NOT the "600W" stuff antique car parts vendors are offering.)
2. What grease can I use in my '72 Dodge van U-joints that have very short life spans now that I'm towing a travel trailer?
3. What grease do you have that's correct for the Vega steering gear in my '32 Ford roadster street rod?
The oil companies have toll free phone numbers for technical support.
