Rebuilding my 727 and I'm running into issues. I've been into many torqueflites but never any with with 300k+ miles. My transmission has issues where the output shaft meets the input shaft. The washer that sits on the output shaft pilot has dug a groove on the inside of the rear clutch retainer allowing the shaft to move around and beat up the aluminum planet carrier. I bought a core transmission to get the parts out of and when I tore it down I found it has the older style large pilot shafts. At first I was happy because its a better design and supports the shaft better but then I realized the output shaft is twisted.
So how did they get away with the newer design? There's almost no support between the 2 shafts, no bushing no real wear surface.



Groove in rear clutch retainer no bushing.





Twisted output shaft





old style input shaft with bushing