th350 output shaft length for slip yoke

[jsburton69]

I was having a vibration at about 45 so I was having the U joints checked and the drive shaft balanced. The shop said the problem was probably because the shaft was too short and the yolk was only going over the output shaft by about 2 inches.

Got the new shaft and tried to install but still only going onto shaft by a couple of inches.

How long is the output shaft of a th350, should the slip yoke be able slip all the way onto the shaft?