I just looked up napa and autozone part numbers for ya and they are both different. 1 ton gas or diesel from napa or autozone is p.n. 88278136 or 7547. For a 1/2 ton its 88278122 or 7533 and the prices are different as well. Could be as simple as the heavier one has a lower ratio

. Find someone with a 1 ton and count the splines on both shafts. If they're the same as yours I would think it would work fine.
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99 QCSB,leveled, ats twins, arp studs,bd155 injectors,edgejuice w attitude, ats intake/exaust manifold,built trans w lockup switch,5" exaust.