The part # is 1B8730.
I believe it is a standard woodruff key- should be a parts/ hardware/ McMaster Carr store item.
Thanks Phil, but the 1B8730 is the key for the D2/D4 pony.....it is 1/4" thick. What I'm looking for is 3/8"thick by about 1 1/4" long. I stopped at a couple hardware stores on the way home and they had nothing that big. McMaster Carr most likely has them but I'm not exactly sure of all the dimensions. That's why I figured to get them from Cat.
Hope someone has that part number handy.....Thanks, John
http://www.mcmaster.com/#woodruff-keys/=j92z5k
My 9U13263 - 9U29764 Parts book shows a 5F8453 part number and no interchange.....might be an odd ball Cat item.