Front Suspension Lower Ball Joint problems of the 2002 Dodge Ram 2500

An excess of 50 thousands of play in the upper and lower ball joints of my 2002 Dodge 2500 4x4 quad cab diesel has been detected by two independent service shops. The dealer, southtown Dodge, refuses to replace the ball joints under warranty, citing only 20 and 24 thousandths play with 30 thousandths allowable. Over the last 5000 to 6000 miles, the ball joint wear has caused the steer tires to wear rapidly and erraticly steers itself when in motion. The dealer offered to replace the ball joints for "around $800" if I am "so concerned.