Anybody running a 700r4 behind an LS? How are you controlling the TCC lockup with the LS PCM? I know I can do it outside of using the pcm, but it just seems there would be a better way. The only reason I am using the 700r4 is because I had it and I have already spent enough money to build it up.

 

For the 700R4 go to Painless and get the part number for their lockup kit, and then do a search on the internet for the best price. The kit will have all the necessary wiring, switches and the needed instructions on how to do this. This will give you 3rd & 4th gear lockup at light to medium throttle, will unlock when going to WOT, and when you let off the throttle, and when you hit the brakes. This kit has been recommended and used successfully for many years now. And, yes it works with large cams too.

 

Since the OP has an LS PCM, the OP probably wonders if the line that goes to the 4L60E lockup clutch soleneoid couldn't be used on the 700R4; IIRC it is the identical solenoid. Of course a lot of codes would need to be disabled and after disabling all the 4L60E codes, the lockup may no longer work.
OP: Therefore, unless you have HP Tuners or a very cooperative local tuner, it might be easily to just take PBA's advice and run the lockup independent of the PCM.