I got my truck level with one trimpacker on the drivers side and with careful assembly. Check all the parts during assembly and put the longer one (the difference will be tiny, if there is one) on the drivers side. My last truck leaned bad, about a half inch lower on the drivers side with 2 extra packers (1 pass, 3 drivers). The idea is to get the tiny amout of variance allowed during production to work for you, not against you. Good luck.