I just acquired a 2007 Silverado 2500 NBS with the Duramax/Allison. The truck was a work truck and I have been fixing small things here and there. One thing I am wanting to tackle next is the shift lever. It engages through the gears very crisply, but there is no resistance on the stalk when pulling rearward to shift. Sometimes I have to jiggle the lever to turn the truck on and to remove the key. I would just like to know what part is worn here and needs to be replaced. Maybe it is something that has just come disconnected, as I have seen many 250K+ mile Chevy trucks with a tight shift lever.