I have done a lot of searching on my trucks problem but can't come to a firm conclusion. The truck resonates/vibrates at about 60 mph in 2wd and 4wd. It is worse in 4wd or when loaded with weight. Also is worse going uphill under throttle. Runs smooth at slower and higher speeds. The tires and wheels are not the problem, I am on my third set of tires and have the problem with summer and winter rims. The problem has been going on for over a year. The dealer has changed out the transmission, right rear axle and seal. I am thinking it is a u-joint problem, cv joint problem, or a front diff problem. The truck is stock suspension and motor. Any toubleshooting tips would be appreciated.

have you check and change diff fluids.. i had a similiar problem with a Toyota Tundra pulling a fifth wheel,and it turn out to be the diff oil was soo dirty that my posi plates where cluttering inside ,especialy when under heavy torque..if you change fluid make sure it full synt. and for posi lock diff...

I changed all the diff fluids to Castrol synthetic gear oil after 6 months. I am thinking when I add weight in the box the driveline angles change. Yesterday I changed the 2 ujoints on the rear driveshaft and relubed the splines. It made no difference. Next step is to change out the steady bearing and ujoint on the front part of 2 piece driveshaft. Has anyone changed out a steady bearing? How is it done?

Did you have the driveshaft itself checked for balance?? I had problems when i first got my used cc max. Search my posts in avanced for PEVOMAN you never know for sure till you can say for sure that it not the driveshaft(s)

Thanks Pevoman. I am going to a driveline shop on my next trip to the city at the end of the month. I'll get them to check it out. Any idea what it costs to have a driveshaft balanced?