A727 Torqueflite planetary question (for gurus only lol)

[Lefty71]

Just a point of curiousity, since I know they are'nt a high failure item anyway, but;

Has anyone ever stacked up rear planetaries from a 70's 727 to compare with the newer four or six pinion planetaries from a later model, like a 46-7RHE or an 48RHE??? Are there physical size, width differences??

TIA, Lefty71

 

[1 Wild R/T]

They have been swapped in before... I don't know the specifics but I know it's been done... I don't have a need, never really had any issues with the three or four pinion units so I haven't really bothered too look.. But I have talked to a buddy that builds trannies all day every day so I know it's doable...

 

[493 Mike]

Output shaft front planet splines differ.
1962-1975 are interchangeable.
1976-1993 are interchangeable.
1994 and newer are interchangeable.
Beware also of planet gear pitch as they also vary.
Keep thrust washers as well as all other components within their year grouping.
Mike

 

[Lefty71]

Beware also of planet gear pitch as they also vary.

Now, this might be the problem.... My thinking was, "keep the rear ring gear with the appropriate vintage output shaft to avoid spline angle issues"...... but then I was wanting to mix and match the rear planetary itself into that particular ring gear, but if the gear pitch itself is indeed different, then no-go..... Thx for your insight.

 

[oldkimmer]

The rear planet doesn’t fit on the splines. This has been answered on FABO. Kim

 

[Lefty71]

This has been answered on FABO. Kim

Thank you Kim, Lefty71