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This would be the only case in an M body that would have had anything electrical to do with lockup. Right up to 1989 the only thing non-cop ones have is the neutral safety switch and everything else is done within the transmission itself.
Mitchel On Demand wiring diagrams for BOTH '88 and '89 Diplomat SE's show a "Part Throttle Unlock Relay" - receives ground signal from the Spark Control Computer (org/blk wire - plug 1/pin 8), and 3 dark blue wires - 2 provide signal and input 12v+ (same dk blue wire from key that powers the coil, volt reg, alt field, etc.) , and 1 providing the 12v+ output from the relay to the "Part Throttle Unlock Solenoid" in the trans.
So, according to Mitchel, controlling the lock-up electronically started in '88.
Mitchell copied the wrong information right out of the factory manuals and it's not the only wrong bit of information in there. Electrical shows that yet the transmission section has the correct information with the valve and pressure spring
and no mention of electronic control anywhere. Trucks might have gone that way but the cars never did.
The Mitchell hydraulic flow chart (Fig 5) also shows the electric lock-up solenoid in the trans in '88.
At this point - my original post was - do electrically controlled lock-up valve bodies exist?
YES, THEY DO. Application?
NO ONE CAN AGREE (Doesn't matter at this point - we found and bought 2 one wire lock-up V/B's). Better torque converter?
NO REPLIESSo our best bet at this point is to just wire a toggle switch to the flippin thing and after we figure out where on and off is, mark it with a sharpie.
The hydraulic chart doesn't mean anything, they would have used one set of charts for the type of transmission and not the application it was going in. If the application doesn't use it they just expect you to omit that information in the manual. The actual description of how it works in the manual and the breakdown diagrams of the lockup components at the vale body do't show the electronic parts. As for application, everyone has agreed that the fuel injected trucks have it. Cars don't. I would take what's been said in this thread over what a Mitchell manual shows.
If was trying to make this work I would get a copy of the factory truck service manual to at least verify the Mitchell information.
John can correct me if i'm wrong but I didn't think under hard acceleration it locks up anyway. Some of those transmissions you can tell when they've locked up by the way it sounds or feels and usually it's when you're already in 3rd gear that it engages.
Pretty much once you've built a 904 to take the power the weakest link is the torque converter snout. After my last 904 died I put a 727 behind my 360 and called it done.
