With the swap I am doing I have the option of wiring my 700r4 torque converter with a switch that would allow me to lockup the T/C in 2nd and 3rd or 4th only at my choice.
I have been trying to get my mind around the value of the 2nd and 3rd lockup and am not sure I see many real world instances where it would be beneficial.
I know lockup creates less heat, so maybe extended driving in the lower gears like on mountain roads... has some value.
Am I missing something?

 

Well, you would think that the 2nd and maybe the 3rd lockup might be handy for passing, but if you floor it, you're gonna downshift anyways. I had a camaro with a 700R4 and the lockup was really touchy in 4th so it would be nice to be able to hold it in there when you needed to.

 

I think I will wire it up for 2nd, 3rd & 4th on one leg and 4th only on the other and see how it functions.
I will post my results.

 

Either way you go, that's a killer option to have at the flip of a switch, good luck with that.

 

I put in a relay with a floor switch in my Toyota auto (343f) for this option. I did it because I have a diesel and try to get really good mpg by going easy from stops. The high factory stall (2200 rpm) makes this a pita so I lock it up @ 15mph in 2nd and then shift through the gears keeping it between 1500-2100 rpm which works great for the diesel. The floor switch makes it nice to turn off and on easily in traffic.

 

Nice! The way mine will be wired I will have 2,3&4 lockup in one position, I will watch what this selection does to the fuel economy... driven slow and easy.
I am installing an LED indicator so I will be able to tell what I have selected more easily. I like the floor switch idea!

 

where did you get this lock-up switch from. cuz i am doing pretty much the same set up as you i just havent decided on runnigh the stock ECU or using the mega squirt 2 system yet.