Performance while at 20-30km/h

Hello All, I have observed a funny "CLUG" sound that send a heavy shock through my pajero sports 2010 while in a traffic jam and the speed is between 20-30km/h, i guess this happens durring auto gear change. Is this problem unique to my pajero or is it a general problem, this is my first time of driving a dessel engine vehicle and am not sure how it really works, i have taken the pajero to a mitsubishi service center but the problem still persists.....any ideas?.....i realy need help here!!!!

Ade

I think it is due to turbo lag if our rpm is lower than 1500..I experience the same once a while....

Hi Matnor, thanks for your view, its good to know its not unique to my PS.
Rgds

Ade