Just about all large jets have Yaw Dampers and most have triple axis autopilots. Several classic Jets had pneumatic, hydro mechanical units that used pitot pressure to restrict rudder movement. Most modern fly by wire aircraft use a number of inputs to dampen and coordinate/control turns along the yaw axis with an A/P engaged. Y/D and A/P control are often different components within the rudder actuator, commanded by flight control computers on separate channels using outside information such as accelerometers to help compute the commands.
The classic 727 had a crude yaw damper, I am surprised to hear the 737 did not.
Last edited by grounded27; 27th Jul 2012 at 23:34.