Transmssion goes KLUNK!!!

[Doru]

This is the 2nd time it happened in the last 2 weeks.
Slowing down to an intersection, pressed the brake to slow down. Coming almost to a stop - I can feel the tranny going in "limbo" (if it was a manual, it's the same feel as neutral), then pressing slightly the acceleration, the tranny just slams in gear - the feeling is like a huge sledge is hitting the car, almost teeth shattering.
I had an almost similar symptom with the e39 - but it happened when I switched from reverse to drive, or when I was on the HiWay and stepped on the gas pedal. The cure then (e39) was an ATF & filter change - fluid was black, magnets loaded and the filter was pretty much clogged.
This symptom (with e53) is slightly different - still in drive, but very slight throttle, after almost stopping.

Anyone experienced this with an 04'-06' ? If yes, what was the cause & the cure. It's a 4.4

Thanks