Well................16k is a little on the light side... My truck is a 06 f350 swr and weighed just under 8k.. Went to the scales and came in at 26062, so with that being said a 4200 is right around 18k!! And to do this with a 2500 , I understand its newer than mine, is crazy... Im an idiot for doing it with a 350 SRW. Granted I only have 2 trips this yr and they are all local, still not good and an upgrade is in the near future but to do this all over the country is just.....well........crazy. Most of the guys I travel with have short boxes with sliders but they rarely use the slider. And only in extreme, tight lots will they use it.. I use the superglide.