The kick-down switch momentarily grounded out the coil so the OD could safely drop out, but only killed engine for a split second. The design of the BW unit meant it couldn't have power to the trans when you dropped out of gear or it put a strain on the planetary gear shafts, eventually causing one to break. The Borg-Warner ODs used a big electric solenoid to engage, the LD unit uses an internal hydraulic pump and solenoid, the electric solenoid in it is just a valve to activate the hydraulic servo. Otherwise you switch it on when pulling in gear, then let off the gas and it will shift into OD. When OD is switched off it should work like a normal auto, but for racing I'd pull the cable and lock it out. Under normal driving it should be just fine, just don't use OD when drag racing if you intend to use it in a street/strip car. The unit itself should be plenty strong, and you say it DID come out of a motorhome. Later, GV acquired the rights to produce the LD unit and made a bit stronger one. GV made custom adapters for the AMC units.
Gear Vendors got their start by buying surplus Laycock-DeNormanville OD unit from AMC when AMC stopped using them.
