'76 front wheel spindle

About 2 years ago I lost a wheel bearing on the left front of my 1976 f-150 4wd. I was in a very rural spot when the bearing grenaded and tossed parts everywhere. I had a lot of my tools in the back of the truck and didn't want to leave it in the middle of nowhere,so I drove it about 5or 6 miles to a golf course I am a member of so I could keep it locked up until I could get it towed to my house.The lockout was hot enough to melt the plastic parts when I finally parked it.Now that you have some history, here is my problem, I went to the local 4x4 shop with the remains after I took it all apart,and the owner looked at the spindle off of my truck went to a bin ,pulled a part out matched them up and said this should work.I bolted all the new parts on and truck works fine... in 2wd when you put it in 4wd you can hear metal on metal not really grinding but a high pitched whine. My question is, does anyone know where I can find the numbers I need to get the parts or what I need to know as far as gear ratios , do the front and rear need to match if I replace the entire front running gear? Can I get just the outside spindle and hub to match somewhere?(no bone yard around here has much in the way of 4wd and when they do get something it is stripped out pretty quickly). Any help will be greatly appreciated ,Thanks