 The layout is based on the K4B 050, which turned out as much more reliable as the previous layout from the K4A 025.With the small block V8 engine M 116 the K4A 040 (type 722.2) as a stronger version of the same design was launched.As a three-speed unit, the W3A 040 and W3B 050 (type 722.0) is combined with V8 engines, and it uses torque converter instead of fluid coupling.