& FYI there was an article way back about 727 failures that was traced to mixing & matching shafts/gears as it seems there were slight changes in spline count or shape of the splines. Kunkel will know. It came down to there were(3) different groups of years in the 70's that the rotating assemblies must be kept together & not mixed & matched. this isn't directly related to the Q but something to be aware of.