my girlfriend has an 85 k5 blazer mud truck that i was playing with the other day and the transfer case confused me. it had 4 4wd settings. low loc, low, high loc, and high. what do the ones with loc mean? do they lock out the differentials? thanks

 

Sounds like you have an NP203 transfer case. This case is a full-time 4wd transfer case. This transfer case has a differential inside which allows for full-time operation without all of the crab walking that happens with typical part-time 4wd transfer cases when in a 4wd mode. The LOC modes effectively lock the transfer case center differential, sending equal power to the front and rear axle.

When stock, the front axle does not have disconnect hubs on it. If yours does, then the transfer case has been modified with the part-time conversion.