I bought a new '92 CTD D350 (rear wheel drive) Club Cab dually with an automatic transmission and drove it for over 100K trouble free miles towing a medium size 29-ft fifth wheel trailer all over the lower 48. The only modification I did other than a fifth wheel hitch was install a Horton fan clutch. The front springs were beginning to sag from the weight of the mighty Cummins and if I had kept the truck instead of trading for a new '97 CTD dually, I would have replaced the front springs and the ball joints as preventative maintenance.
Bill