Doing a complete tear down and inspection of a 1990 Cole superhawk with 565 chevy and Bravo drive. Found the Vertical shaft splines twisted below the coupler. Checked everything else in lower housing out and all looks good. Merc manual goes thru all shimming and pinion height checks for reassembly. Is this all necessary if your reinstalling all the old parts on a new shaft? I can see this if you changed something like the driven gear or pinion gear. Tooling is almost as expensive as the parts and I dont want to outlay the money if its not necessary. Also can any one tell me how to remove the check ball assembley in the upper housing that allows the drive oil to enter from the resivoir bottle. I have the plunger out of the bell housing but cant see how to remove the assembly in the upper drive housing. My first time going this far into a stern drive so any help would be appreciated.