Interchangeable TH400-parts

[Caddyswede]

Can I use parts from a Pontiac TH400, maybe from 1976, to restaurate my Caddy TH400 from 1968? It looks the same except tailhouse.

[STDog]

Can I use parts from a Pontiac TH400, maybe from 1976, to restaurate my Caddy TH400 from 1968? It looks the same except tailhouse.


Mostly.
The internals are the same for BOP(and cadillac) or Chevy cases/bellhousings.
The tailshaft housing and the shafts that match them vary for the 3 different lengths.

Early TH400 used a sprag instead of a roller clutch on the intermediate drum. The drums ar different, but interchangable if you keep the matching clutch. The '68 will have a sprag, and the 76 a roller.

There's the even earlier switch-pitch differences, but you not likely to find one of those.

[montrosepatriot]

The internals from a Chevrolet/GMC P-series (box van) and Humvee retained the 1965-69 clutch drum, which replaces the 70+ drum.

4L80E internals interchange with THM400/3L80s (some 4L80E parts are exclusive - oil pan, oil pump, torque converter, valve body, shift solenoids) - there is a usual inventory...