The lower pulleys on my G4200 Hydro are loose. I have a parts manual I have been studying. The 2 pulleys come apart. The first pulley slides onto the pto, then a snap ring, then the second pto. This keeps the pulley assembly from sliding back and forth. My problem is that I can't slide the assembly onto the pto far enough to let me put the snap ring in the proper place. It's almost like the pto is 'sucked' back towards the mower deck. Any suggestions before I tear it down further?