The standard GMT-400 truck body door handles are designed to be mostly flush with the body. The handle is inset and lifts upward to activate the opening lever. The handle and bezel assembly are seperate pieces cast out of a cheap 'white metal' mix of aluminum, zinc, and generally whatever cheap 'pot metal' was available. This is not an intrinsic weakness, but when combined with the upward lift of opening the door, it can commonly lead to stress fractures and breakage over time.
While direct replacement handles (used or aftermarket) are available, they are made of the same materials and subject to the same weakness.
The Kodiak/Topkick/3500HD(1994 and up for 3500HD) door handles from the same period trucks used a different, more industrial designed handle. Rather than lift up to open the door, the handle has a lever behind the handle grip that is squeezed to activate the mechanism. This provides several benefits: the door is more easily opened from below, standing on a truck step since the user does not have to lift up. Also it makes the handle more durable. These handles are almost directly interchangable with the standard handles, as long as the correct lever and lock rods are used.
Conversion from standard handles to the commercial style door handles offers several advantages. The durability is a factor, but the standard handles are also more easily pried out and defeated in a break-in event. The commercial handles overlap the door more, and provide better security against prying. For crew cab or suburban rear doors, the same handles may be used with the lock holes blocked off or blanked out, or dummy locks placed in the holes. The same can be adapted to suburban rear doors for the GMT-400 body style. In order to convert the handles, the correct lock rods for the commercial handles must be used.
Parts availability: while the door handles themselves are readily available from the aftermarket, the rods are not available and are no longer made, stocked, or available from GM directly. In order to complete the conversion, the rods must be obtained also. Many used parts suppliers will not sell only the rods, so this can be expensive if a source is not available.
Parts list (GM part numbers):
15619625 RH handle
15619624 LH handle
15558837 lock cylinder rod
15558838 lock cylinder rod
15647187 LH handle to latch rod
15647188 RH handle to latch rod
15619623 RH Lock pawl
15619622 LH Lock pawl
20633148 rod clip (Need Two)
Commercial style door rods (lock rod on left, handle rod on right)