r230 walk jumps out

Hello dear community, On the first nice weekend of this year, the following happened: With a bit more speeding everything was fine (automatic switch down and switched the gears off.) when I went off the gas again he tossed off and then turned down (the switch down felt a bit tremble) when I pressed again on the gas pedal, it was as if the selector lever was on N, but it was still on D. The whole thing came up 2 times. Then everything was again I.O. Otherwise he really switches butter soft. he is Bj.2002 and has 96tkm on the clock. Nights week I give him in the workshop. Does a hint of what can come to me? Mfg Berti