The truck has 111,000 miles on it ,so it is probably all of the above. The tires only have 10,000 mile though. I will start with another tire rotation and balance.
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THERE'S GOTTA BE A BURRITO JOINT OPEN AROUND HERE!
also check your front rotors, they might be wrapped from excessive braking (heat build up) from towing w/o trailer brakes
if no luck go to, the dieselgarage.com and post on that forum for additioal info