I will add this,
I watched a friend trailer his rig to tellico, wheel 3 days, then blow the trans on his towrig 3 miles into the trip home leaving him stranded...his trailrig was fully operational and would have driven home.
Nothing is fool proof
09 Dodge 2500 w/ a Cummins, dd/towrig
85 Toyota Pickup, 1tons, coilovers, 40's, ect