Aside from the 'usual' or 'normal' replacement items for the PSD, these significant parts are original to the 10/94 build date:
front and rear suspension(replaced all four shocks twice)
two of the injectors
rear brake drums(not a fan of turning them)
original ZF 5-speed rebuilt: 322,416
4.10 ring and pinion twice, converted back to old dino 85w-140 and Mag-Hytec cover
4 vacuum pumps
parts replaced at 500,000+:
all the original rad and heater hoses, water pump(yes, still had the factory clear coat) crank dampner and front seal: 503,161
HPOP, IPR: 508,870
The truck almost always has at least a 6,500# trailer attached...been a real work horse!
Update as of yesterday: replaced another cooked VC gasket, VC pigtail and all GP's(had 246k on them) on the driver's bank. Replaced original PS pump(reservoir leaking, pump still good) after getting tired of topping off before each trip.