74 blazer NP205
 

My NP 205 is bullet proof but is leaking out of the cover for the rear axle. Anyone can tell me what this cover is called? Also does anyone know the in's and out's of swapping the stock 12-bolt rear with the heavier 14-bolt rear? I have heard that it is a direct swap. I don't have to change the spring perches or the shock mounts?

Thanks,