Restoring a 1970 Cutlass Supreme with a TH350. The driveshaft was removed from the trans when I bought the car. Trying to re-install the driveshaft and the slip yoke will only go on about 1 inch then gets hung up. I picked up a used BOP TH350 that was working fine. The original is probably in need of rebuild anyway. Have the same issue with the used one. Slip yoke goes on easily about 1 inch then stops. I've cleaned surface rust from the inside of the Slip yoke and it doesn't look bad. I'm sure the tolerances are slim. Any suggestions on how to better clean the inside of the yoke or where to get a new one? Having a hard time finding a new one on the web with the inside u joint retainers. The yoke looked original with the inside u joint clips and the factory resin holding the joint.

Thanks!

 

Small files and picks should be enough to clean it up.
You'll probably have to get a 1350 style yoke and a conversion u-joint (1350 to 3r). Replacing the original u-joint is probably a good idea anyway.

 

Remove the tail shaft, easy to do in a TH350. I had that issue, there was a metal sleeve inside the trans for some reason. Once removed, no issue installing the yoke. Yes, there are multiple conversion U joints, I need a 1330 to 1350 on my 4L80E swap using a different driveshaft. Some new 3R yokes still exist. I came across one in a 32 spline version for a TH400/4L80E. I'm sure a 27 spline exists new as well.

 

That metal sleeve is probably a bushing intended to locate the slip yoke. If worn nor damaged, replace it with a new one. If a small wire brush doesn't fix the fit of the yoke, replace it.

 

^^^THIS! The yoke is centered by the bushing in the tail housing, not by the output shaft. Removing this bushing guarantees that you will experience premature wear on the output seal and probably vibration in the driveline (and possibly damage to the internal bearings/bushings in the trans). What does the OD of the yoke look like? What does the ID of the bushing look like?

 

No, I know what the bushing is, always replace it with the seal. It was a machined piece of long, fairly light tin. I thought it was weird it was in there, almost looked like a factory oil deflector.

 

Can't say that I've ever seen that before.

 

Thanks for all the info. I'm going to try to clean it more with a pick and file. In the meantime, I ordered a new yoke and conversion joint just in case. Thanks again.

 

Filed it carefully between the splines with the edge of a file that fit and finished it with a brass bore brush. Slides on and off as it should now. U joint replaced as well. Thanks again.