I have an '01 Dodge 2500 w/CTD H.O, 4X4, 6spd.  The truck has 171k on it, mostly highway, and I'm having 2 problems. The first is my driver side front tire is starting to cup, the passenger side is showing signs as well but not as bad. Everthing under the truck seems tight. Correct and equal air pressure in the tires. Very little wander on the road, truck doesn't pull left or right.  The other problem is a driveline vibration. All u-joints appear tight, hanger bearing recently replaced.  Vibration starts @ 54MPH then goes away @ 58MPH and continues off and on at different higher speeds.  With a 8000lb load on the truck it doesn't seem as apparent.  I intend to keep this truck and want to fix it right, I do almost all mechanical work myself, no good mechanic in this area.  Anybody had these problems? Thanks.  

You did well to get that many miles out of front axle. The weight of that Cummins (about 1300 lbs) is hard on front axle pivots. You need to have them replaced. This is kinda a well known problem but they never talk about much. In 03 Dodge quietly dumped the D60 and started using a different front axle made by AAM with much bigger and stronger knuckles and ball joints to address this. So, you have two options, rebuild current front axle (it will not be cheap) or if you plan to run it for many years give some serious though with swapping out front axle from a 03 or later model Dodge truck from a bone yard source. The newer axle is very beefy looking even compared to the D60 it replaced. Myself, I would use second option if I planned to run it a long time.  

Thanks for the info.  I'm gonna start looking for one of those axles.  Any idea about the vibration? Could it be result of the same problem? Sometimes going around a curve while its vibrating makes it go away seems like but I could just be losing speed and that makes it go away.  

cumminspower:
Thanks for the info.  I'm gonna start looking for one of those axles.  Any idea about the vibration? Could it be result of the same problem? Sometimes going around a curve while its vibrating makes it go away seems like but I could just be losing speed and that makes it go away.

Drive line vibration can be a bear to track sometimes. Given mileage on truck and torque on drive line I would replace Ujoints in rear drive shaft because sometime that can feel tight but still have some uneven wear in the that shows up as a vibration at times. Also you mentioned the you replaced a hanger, I assume you mean carrier bearing assembly. It this was not aligned properly it can cause vibration too. One more "tip", many years ago (over 30 years) I had a old 66 chevy 3/4 ton truck with a 2 piece drive shaft and carrier bearing. It drove me nuts trying to get a vibration out of it and since it had a 4.57 axle ratio  the drive shaft was wound pretty tight RPM wise on highway. I finally cured it by removing the complete drive shaft assembly (shaft and carrier bearing) and taking it to a drive shaft shop and having it properly balanced. It was a 100% cure in my case.  

Many thanks for the good advice on both problems.