My car is a 1966 Skylark GS. The car was originally equipped with a Super Turbine 300 automatic transmission. When I purchased the car, that transmission had been replaced with a THM400 ( got the original in the deal). I've had a vibration and noise issue since I purchased the car. A shop has found that the drive shaft can not be properly balanced and has suggested replacing it, including new universal joints and yokes at both ends. The question I'm now facing is that it appears as though the current shaft had to be cut in order to fit the THM400. That shaft will be used to provide the demensions for the new shaft. We have noted that there is very little, if any, end play at the transmission yoke end of the shaft. It appears that the fit between transmission and pinion yoke is quite tight. Can anyone provide advice as the the amount of end play one should expect for good, smooth performance? Thanks!