Mike i thought you had a auto 
nope V6 5spd!
Fluid, I put fresh synthetic in it about a year ago, maybe it scrubbed all the sludge out of the bearings/syncros, now they are loose? ( not sure of the trucks history for the first 90k of its life) I'll try the heavier oil first then save my pennies for one of marlins units with a lower gear set!
