I put it into gear and it dies.

i agree about hooking up the kickdown correctly. it's not just a kickdown cable, it controls line pressure in the box. if it's not right the box may last 10 miles if you're lucky. a temp' fix is to zip tie the kickdown lever on the box about halfway through it's travel. that'll keep line pressure ok to use it. and before anyone says not to do that it won't work i've had both 727's and 904's like it for a long time as daily drivers that got driven hard.
neil.