Went to look at a truck . It's a 90 W-250 727 250k std. cab, clean & straight. He wants around 5k. Drove,stopped and turned fine but at idle it vibrates, not like my 89ctd but like a COE w/855. I looked at all three mnts. , to see if the exaust was riding the cab, got down by the rock guard to hear the converter, checked interior screws, everything seems ok. I've only driven mine and a friends ctd, they seem like /6's next to this, any input, or things to look at regarding w/fwd appreciated, it's my first.