At a very low speed <15-20mph when breaking and then through the very beginning of the acceleration. I've been looking this up like crazy for the last couple of weeks. I'm hoping its a fluid issue, so I scheduled a transmission drain and flush for Wednesday. Supposedly from what I have read (and through intense interrogations of the other drivers in my family) my transmission was probably overheated by my wife or son out driving on the beach (majority of my off-roading here) and my fluid got cooked. They refuse to lower the air pressure when they go out basically out of sheer laziness. If the shudder goes away after the flush, I should be good seeing the relatively low mileage, or if it doesn't, then I may be looking at a mechanical issues (torque converter maybe?) but I'm praying that isn't it.