Don't confuse the 722.6 with the Ford transmission (I've had both). The 722.6 converter clutch is programmed to engage in all gears and is also programmed to operate with a measured degree of slip.

Mine would groan at speeds between 30 and 40, especially if I let off the throttle and got back on the throttle.

The 722.6 doesn't have a valve body in the sense that the old M-B transmissions did either. They don't even call it a valve body anymore (and it is a lot less expensive). They call it a valve gear and it is basically a way to port fluid from the solenoid valves to the clutch packs.