Hi Vile:
Thanks for the lead...actually all the info on the switch pitch (variable pitch) TH400 is very interesting. I dont think I have a SP TH400 in my truck though, because the SPs were originally made for CBOPs (Cadillac, Buick, Olds, Pontiac cars) for a few years in the mid-60s and I believe a TH400 for the CBOPs had a different bellhousing pattern to their engines from the Chevy engine. I do not have an adapter plate between my TH400 and 350 engine, so in my mind that indicates I do not have a SP. Furthermore, I have a ID plate on the pass side of the trans that has "78" for the bottom left stamping which indicates that it is a 1978 manufactured trans. So I do believe it came from a 78 model Chevy of some sort. I looked at the 77, 78, 79 truck wiring diagrams and do not see two wires coming out of the trans connector (only single wire) so I do not think it was a truck trans originally. Possibly it came from a large car. Wikipedia has a good write up on the TH400 (TURBO HYDRAMATIC) and they say that the second wire from the TH400 elect connector is for a trans signal to retard spark timing...so maybe this is why it is clipped off since my 76 has no such feature. Anyway, I have repaired my kickdown wire and reconnected it and will just leave the sleeping dog alone. Next time I have the trans pan off I will take a look and see where that second lead on the trans elec conn goes inside the trans.
BTW, does anyone know what the code of "CM" indicates on the TH400 trans ID plate?
Regards,
Henry