Check this out:
Dan The Gear Man® Tech Note: Ball Joint failures on 2000-2002 Ram Trucks is a reoccurring problem that will probably plague these trucks for their entire life due to the size of the Ball Joints and the steering geometry of the 2000-2002 Dana 60 Front axle.
The Upper and Lower Ball Joints on these axles are at different angles, in other words the vertical axis of the Upper and Lower Ball Joints are neither in-line or parallel to each other. To compensate for the different arcs of each Ball Joint during turns, the modest sized, straight shank, .855" diameter stud of the greaseable Upper Ball Joint is vertically floating in a plastic sleeve. Consequently, the Upper Ball Joint does not support any weight, it merely keeps the knuckle in place. On these axles, the Upper Ball Joint is not really a Ball Joint at all, instead it is a floating King Pin that is smaller in diameter then King Pins found on 1966-1981 Ford F100 4x2 1/2 ton trucks and light 3/4 ton trucks with GVW's of 4,700 lbs-6,900 lbs.
The non-greaseable Lower Ball Joint is load bearing, in fact, the two Lower Ball Joints carry 100% of the front axle weight on your 2000-2002 Dodge Ram 2500 or 3500 truck. Dimensionally, the outside diameter of the Lower Ball Joint is only 3.5% larger than the Ball Joints used on 1972-1986 Jeep CJ's (and other light-duty models of that era) which has somewhere between 1/4 and 1/3 of the front axle weight of the Dodge Ram, plus both the Upper and Lower Ball Joints on the CJ are load bearing. In addition, the Ball Joints used on older models like the Jeep CJ and 1994-1999 Dodge Ram 2500 and 3500* shared the same vertical center line axis and were pre-loaded to compensate for wear. With the 2000-2002 front axle steering geometry using differing Ball Joint angles, no preload is possible, therefore, any wear means loose Ball Joints.
Yes, lack of lubrication with the non-greaseable factory lower Ball Joints can be a factor; however, very few of the failed lower Ball Joints we cut apart are suffering from a lack of lubrication. Replacement Ball Joints in both greaseable and non-greaseable versions are available from us, plus there are even offset upper Ball Joints out there (which in my experience is both short-lived and of limited use). Installing Greaseable Ball Joints and regularly greasing them may provide longer service life, but with the 2000-2002 axle, chances are you will still need to replace the Ball Joints every three to five years. One would not mind the relatively short Ball Joint life so much if these trucks steered better than previous models, were not subject to "Death Wobble", or had longer tire life.
I do not find any allowable Ball Joint tolerances in my Factory Dodge Ram Truck Service Manuals. Generally, with a solid axle, any side to side play is grounds for replacement. Some slight vertical play is probably acceptable for these years.
*1994-1999 Dodge Ram trucks with the Dana 60 Front Axle have Lower Ball Joints that are nearly 10% larger than the 2000-2002 axle. Average Ball Joint life for 1994-1999 trucks is close to 150,000 miles or 7 to 10 years. All 4 Ball Joints for those years carry weight and are pre-loaded to compensate for wear and dampen steering shocks.
Credit to: Quad4x4.com and "Dan the gear man"
I crawled under mine and it is in fact like this. Apperently the 00-02 are the only axles with this set-up.