Which model was the tractor from? There were 3 different lenght driveshafts.One was for the 1250-1477 one for the 1886-01-04 and one for the 1886-05 thru HT23.Does the driveshaft have a lock collar on it as that will not fit the early 1886 as the did not have a slot on the pto shaft to lock the collar on.
According to the 1971 Bolens brochure, the 1476, 1477, and 1886 ALL had the lock ring coupler PTO.
There was an article in Popular mechanics in 1971 that mentioned it quite favorably as well when the did a comparison of the 1886 and 3 other "BIG" GTs of the day.