I just rebuilt my pto on my 106 but within minutes of running one of the bolts begins to vibrate loose. Ive pulled it multiple times and cannot seem to keep them tight. The nuts are to thin to get two wrenches on to really tq them. Ive tried loctite and then safety wire on the remaining threads but nothing has worked. I'm thinking of going to a nylon lock. I'm tired of pulling this pto over and over again

. Ive followed the book line for line but just cant get the lock nuts torqued enough due to how thin they are. Any tips?? Thanks in advance