Abs pulses the brakes preventing the wheel from becoming locked hence the name anti-lock. Braking force is applied on-off-on-off rapidly. With no abs the driver slams on the brakes the wheels lock up and it's downhill from there. With abs the driver slams on the brakes but they don't lock, the brake application is pulsed to allow some wheel spin along with pulsed brake application. The theory is the vehicle will stop faster and under better control than just fully engaging the brakes and letting the tires drag the vehicle to a stop. In the 929 trucks, in a quick panic stop, the driver would over-apply the brakes and with no abs the wheels would lock. With the wheels locked and the torque converter not yet disengaged, the drivetrain would come to a halt, stalling the engine. No engine power equals no power steering which means basically no steering so panic stop loss of control you see where this is leading. So in comes the military and the add antilock brakes as a bandaid. But if you read about the problem it would appear that the torque converter is the real culprit, if it would unlock then the engine would spin free to idle and no stall. Not that abs is a bad idea it's great to have but retrofitting the converter would seem to have made sense.
No engineer thought out or tested that piece of' @@@ERR 'equipment' but probably the same team that thought 'let's design a handbrake that the driver can easily knock off, and have the fully loaded truck run away (every time the driver exits the cab!).
ABS, does not judder the brakes on and off. The sensors on EACH wheel have a rotor on them which lets the driver brake at will, But if one wheel 'stops' (starts skidding) the computer measures that differential speed rotation and removes the braking pressure from that ONE(only) wheel. (and) when the rotation becomes equal again, the computer will ALLOW the full braking effort back on that wheel. If it still skids (slips) the computer promptly take the pressure off again. Hence the feeling of a 'judder'. (as this process is happening very rapidly indeed) ABS does NOT prevent skidding. Doubt this? Well visualise 3 wheels on full release! and your trying to turn and stop somewhat quickly..
Like all things safety wise, this is an aid to further assist sensible careful and considerate driving allied to the pertaining road conditions.
New to the hobby drivers of older large trucks in the hobby should be aware also that some of these older 5 tons have very little power steering assist at low rpms in a higher gear. (as in slowing to a stop without changing down..and entering a steep turn to a driveway etc.) My 1/2 penne'th