I have a 01 Buick LeSaber and recently changed the trani fluid and the filter hopeing to correct my problem. The problem that im having is that sometimes when i take off from a dead stop the transmission will shift real hard to where you feel and hear a hard crack. That is why i had the fluid and filter changed thinking maybe this was the problem. The garage put it on the computer befor changing the filter and fluid and didnt find anything wrong . So i thought it best to have it changed for maybe correcting the problem.

It dont do it all the time just intermitenly. So Thats why i need your advice as what to do. The garage told me if it happens again to bring it in and they would keep it overnight, but since it dont do it all the time i dont think they will be able to help me.