727 Output shaft question

I recently had a spare 727 trans rebuilt to swap into my 67 Belvedere 383. The trans that was in the car is in good working condition, just leaked at the selector seals, planning on using it in another project.

The driveshaft has always been a PIA to get in and out because the slip yoke would bottom out in the trans, although it wouldn't touch the rear of the output shaft. I checked this with some grease on the end of the output shaft, it didn't touch the bottom of the yoke. Splines in the trans are straight and yoke slides in freely. You had to pry and rotate the tires to get the driveshaft in and out. Has been like this for 8 years. We dropped the pan and everything is clean with little material in the filter, about 10,000 miles on unit.

The rebuilt trans went in and the slip yoke slides in about 3/4 in. more, it does bottom out on the end of the output shaft. Installing the driveshaft is now as it should be. The output shaft sticks out of both trans. the same amount. Looks like the splines on the old trans don't go as far up the shaft as the rebuilt unit. Neither trans are original to the car, and both have been rebuilt at least once. Any thoughts as to why the difference in length of splines between the 2 transmissions?

Could be an older one and later one had been up dated with longer spline... to solve that problem... it shouldn't bottom... there should be some play In it about an inch so it doesn't bind when the suspension moves. I've had this problem with u joints wearing out real fast

Maybe your drive shaft is too long. A problem a lot of us wish we had!

bigblock said:

Maybe your drive shaft is too long. A problem a lot of us wish we had!

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The driveshaft is the correct length, works fine in new trans.

68sportsatelliteragtop said:

The driveshaft is the correct length, works fine in new trans.

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If it is bottoming out against the trans tail shaft, I don't think it is. Did it come from a CORONET or CHARGER perhaps?

GTX MATT said:

If it is bottoming out against the trans tail shaft, I don't think it is. Did it come from a CORONET or CHARGER perhaps?

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Read above, it is bottoming out on the splines of the output shaft, not touching the end of the shaft....
Driveshaft fits fine in different trans.

It may be a year thing? I haven't had that issue, so I never looked that close at the splines on the output shaft, but between 1966 and 1967 the number of splines on the input shaft changed. I found that out when I tried to install a performance converter on a 727 in my '67 Coronet. Maybe there was a change in output shaft too?