Is there any difference between the drum brakes on the 4WD vs. the RWD? I'm looking at a kit on rockauto but it only says it fits the 4WD.

 

Um, 2WD is 5 lug and 4WD is 6 lug, for one major difference. 4WD is larger diameter, so the shoes won't fit your drums. So stick with 2WD specific parts.

If, by chance, you are thinking of bolting on a bigger brake set, th3 4WD parts won't fit your 2WD rear end and I believe the 4WD axle, drum to drum, is wider.