Automatic transmission problems

[Yamaha man]

Hey Guys. I bought An absolute lemon Hilux surf. 1998. Very long story short... ended up chucking the 1kzte and fitting a v6 Essex. Now we have trouble getting drive from the auto transmission. If i disconnect the solenoid valve located at the back of the box, i can get drive.

my question: what activates this solenoid?
can i bypass this solenoid valve?
thanks guys°

[budweiser]

B6? Or v8?

[Yamaha man]

V6 Ford Essex uprated motor. So i have no comms between the engine and the box. I did install a tdc sensor and linked that to the ecm but still no luck