hi all im looking for info for tranfer case replacement wat yr mazda pick up will fit my 1993 b2600

wat mine does right now is wen it get hard to haul itself and starts to push hard in snow or mud etc well it kinda make a chirping noise like splines just grinding up it kinda pings in my rear driveshaft to please let me know if u think it is not my t-case
and also are these transfer case chain or gear drive
so from wat yr and model can i look fo that will fit
and also is there any engine i can swap that will be direct bolt in?

thank you for reading any help appreciated