I agree and that is my point. Warranty aside which is understandable, the diesel motors have so much torque you can save considerable w&t and gas my locking up at 1700 rpm. Furthermore when using cruise control, the programing is very binary inasmuch as a decline of 1 mph is sufficient to command nearly full throttle to maintain speed and thus unlock the t/c. By overriding this unlock because the speed sensor shows the vehicle to be above the preset unlock level, the throttle command will increase boost but will still allow the t/c to remain locked and thus keep gas, noise and wear at lower levels.
One of thje problems with the E series vans is that the wiring color codes differ from model to model and only people who "know" transmissions can find the cables that transalte to the programming isntructions for these t/c lock devices which are exclusively made for the F series Ford trucks and ignore the existence of the E series config.