I went to the library, the O'Reilly's, and the Jeep dealership, and none had any information on the thread size. I've measured many threads over the years, and I checked the dimensions in Machinery handbook, so I'm confident of the 7/8-20.
Don't worry about the fax - I think I've found enough specs to do what I need.
Every book I've read about this said to use a new pinion nut when reassembling. The guys at the dealership said they just use the old nut over again. (Is that a scary thought?) A new one will cost $11.25. I also need a new yoke - dealer cost $94.50. Sheesh. I told them I'd think about it, and ran home. Found the parts in 4WheelDrive catalog, at $32.95 for the yoke and $4.99 for the nut, which comes with a new seal. Tax, shipping, handling, bribes, and everything altogether is less than $50. Will be here Wednesday.
By the way, I got the old style yoke, with u-bolts instead of straps, since that's a much stronger design.
Enough of this rambling. Good luck with your project.
"People sleep peaceably in their beds at night only because rough men stand ready to do violence on their behalf." George Orwell