Why does it jerk between 1500 and 2000 rpm while changing gears (automatic)?

Hi,sometimes this can be becouse the filter and transmition fluid need changed,people tend to ignore this area but its just as importent as changing the engine oil and filter,also there is a additive you can use that helps to make things run better inside the transmition its cald,(xado)you can find this on ebay,I drive a mercedes and always use this product it dose work.
I hope this was some help,and just to say I dont sell or make any money from these people who sell xado I just know that it works,all the best.