First let me say that - yes I have searched. I have completed 2 of these swaps (well almost completed) so far. The first was a 97 auto ECM and wiring into a 93 with manual trans. This swap worked out very good by simply making the ECM think that the auto was still there and in park all the time.
The second swap is a 97 auto ECM and wiring into a 92 with 340H auto. The problem I am having is finding any wiring schematics that actually show the wiring that goes to the solenoids in the transmission. I can find the wiring for the Park/Neutral position switch for both years but nothing pretaining to the solenoids themselves.
Am I simply overlooking these? Please help.
Also, let me say, that without the help of Yotatech and all of those who have done this swap before me - Thanks for everything. Definately could not have done it without you guys.

 

Jason or UkRunner (which I think his name is Jason too) are the guys to ask on this I think.

Jason (my name too!!)

 

Ride4fun, I am in the process with the same swap, 89 pickup with the 340H. I have read on here it has been done. However, there are a couple of things to keep in mind. The first is the speed sensor, I am using a T100 donor ecu, as they read the same. However, there are 2, one is located in the combo meter and is the fail safe. Now there are four solenoids on the 340h, the fourth being the transfer L4. The 3.4 used the 340f, which has three solenoids, none in transfer. Connect the S1, S2 and SL (S3) as usual to 3.4 ECU. The S4 you will need to connect a normally open relay to control L4. The S4 solenoid is at 0 volts when you are in H2 and H4, but when you put your transfer into L4 the 4 solenoid is suppose to get 12 volts to activate. I am sorry, as of now I only know the theory. If you search from the beginning (last page) of the 3.4 swaps, it has been talked about but no "how to" that i could find.
Jeff

 

Ride4fun, I am in the process with the same swap, 89 pickup with the 340H. I have read on here it has been done. However, there are a couple of things to keep in mind. The first is the speed sensor, I am using a T100 donor ecu, as they read the same. However, there are 2, one is located in the combo meter and is the fail safe. Now there are four solenoids on the 340h, the fourth being the transfer L4. The 3.4 used the 340f, which has three solenoids, none in transfer. Connect the S1, S2 and SL (S3) as usual to 3.4 ECU. The S4 you will need to connect a normally open relay to control L4. The S4 solenoid is at 0 volts when you are in H2 and H4, but when you put your transfer into L4 the 4 solenoid is suppose to get 12 volts to activate. I am sorry, as of now I only know the theory. If you search from the beginning (last page) of the 3.4 swaps, it has been talked about but no "how to" that i could find.

 

This has been going back and fourth for about 5 years: https://www.yotatech.com/forums/f160...-a340h-128200/

Might find some more info there.