Power or economy toggle for turo 400's!

[GMC AMI]

Since this is such a decent truck board I thought I would share a little trick
I learned by fooling around. I have a turbo 400 transmission mated to a Caddy 500 in my 82 GMC. If you put a toggle switch in line on the 12 v wire that runs to the transmission you can turn off the power to the tranny and have
delayed shifting, this is power mode. With power on the tranny shifts into drive around 30 mph, fuel econo mode. With power off the truck runs out and shifts about 3800 rpms which with a caddy 500 tears your head off when it up shifts. You can adjust with a scew on the tranny to your preference on when you wish it to shift. Worked great at the drags for consistant runs.
Have fun, it works great, keep on trucking!

For any non-believers just unhook wire to tranny temp. and see if shifting is not delayed. Seeing is believing! This is a 1976 turbo 400 Caddy transmission.

[MylilBowTie]

I dont see how that does anything? Are you talking about a SP th400? Only wire going to most th400s is the electric kickdown (3rd to 1st).