More on Overdrives

John Slade (edalsj(at)igs.net)
Thu, 13 Aug 1998 11:50:23 -0400


The previous thread on overdrives left some unanswered questions, and I just found a publication which may answer a couple of them. In the bottom of my bookcase I discovered Haynes book #033, HILLMAN/Chrysler HUNTER & MINX, 1966 to 1979, plus Singer, Sunbeam and Humber variants.

Chapter 6 gives the usual thorough coverage of the manual gearbox and the Automatic transmission, but also gives quite good descriptions/instructions and exploded view diagrams for both D-type and J-type overdrives. I have not found, in the book, any reference as to which overdrives were fitted in which models. From the detail of the exploded view diagrams, however, it does appear that the D-type overdrive has a coarse splined output shaft, while the J-type has a fine splined output shaft. If the drawings are any indication, it would appear that either type should fit in an Alpine, provided the correct output shaft connection can be made.

The book also has the circuit diagram (same for both overdrives) , with switch and relay details such that if the original bits aren't available, a replacement could easily be made from generic components.

John Slade Manotick, ON