Not exactly sure how to describe it. But it seems on most 844 lulls that if you have the boom raised up and level the machine sometimes coming down something locks up and causes the machine to jerk. I think something in one of the pistons to level the machine gets locked up. That's best I can describe it. It seems to happen in alot of the ones I've used. So probably a lingering problem all around?
What you are feeling is the rear oscillation lock out disengaging when the boom comes down below a 40 degree angle. Totally normal.
Sometimes it is quite a forceful jerk to the machine. Even coming down slow. Cause I can tell when it might happen. It's never good when you have a load on it.
I'd hazard a guess that you are driving withthe boom up, otherwise it shouldnt be that noticable.
Make sure your " AUX " switch is in the middle or off position. If you have a continuous flow valve (look in your operator's manual) turn the knob all the way counter clockwise.