What loader do you have? Is this a John Deere kit? Do you have a link to what MPW10039 is?
Thanks for the link.
Did you see it's for 410, 420, 430, & 460 Loaders? No mention of 70A loader. Did 70A replace 4x0 loaders?
Date on instructions was 15 JUNE 2000. How old is your loader? If newer than 2000 it may be updated already?
There was a note for 855 & 955 tractors REWORK & Drilling required. See dealer for installation. also see page 6 of the instructions.
I think I would start by asking a JD dealer to print out the instructions. Then read thru them
Is it getting the handle to slide and disengage the lock up front?