I tear down and inspect a General Motors (FM) Chevy TH475 aka TurboHydramatic 475 (TH400 derivative) out of a 1980s motor home, go through the points of inspection, cover differences and changes through the years as well as parts interchange.

Everything mentioned applies to the TH400 as well; the only material differences between the TH400s and TH475s are the flanged bolton yoke (some models of TH400 have these also), extension housing with roller bearings and straight cut gear sets installed for added strength and durability. To my knowledge, no other TH400 variant came with all of those installed in the same unit. That said, you can move an entire TH475 gear set including the center support to the rear ring gear as a service pack into any TH400 just install whichever output shaft and ext housing corresponds to your application).

The video is long and there's quite a lot of information, both given verbally by me and in annotations so feel free to skip around using the table of contents below.

0:0010:14 Intro and Drum Brake
10:1531:58 Exterior Case
31:5948:26 Case Belly
48:271:01 Case
1:011:49 Sub Assemblies

Need some information quickly? Try my TH400 Fast Facts sheet: https://docs.google.com/document/d/14...

Looking for a TH400 core from a specific year, make and model or seeking to verify same? Check out my TH400 ID code spreadsheet here: https://docs.google.com/spreadsheets/...

All information on the spreadsheet is courtesy of Ron Sessions' "TurboHydramatic 400 Transmission"