I am sure some will answer with the exact answer but the wires on my th400 go to a micro switch on the carburetor linkage so when you go wide open throttle it kicks the trans down. Dave

1941 Chevy
"First rebuild - complete!"
Follow the story in the DITY
1941 GMC resting peacefully
1946/1947 Chevy Street rod on s10 frame complete
1945 GMC panel truck in line for restoration
1941 Plymouth stock complete
1941 GMC COE in restoration process
Read his Project Journal
1941 Chevy Coe uncertain future resting now