I too have the same poblem and have not been able to fix it. However from what I have learned about transmissions, reverse has higher main line pressure then forward gears to compensate for the reduction in clutch pack surface area. This essential means that when shifting into reverse the pressure is raised by quite a bit and this is why you feel surge. But obviously this should be transparent in a car so why does it happen now? I can only guess that without the ability to change the filter build up occurs and slows the ability of the valves to change pressure.

If you bump the car into neutral while still moving forward then shift to reverse after stopping this will stop the clunk. Not a cure, but a bandaide.