1995 Silverado POWERTRAX POSI
 

hello everyone,
I have a 1995 silverado 2WD WITHOUT posi. I've been looking at a powertrax posi for the rear. Im having trouble understanding if it will truley lock both wheels when needed, because it says it will send power over to the wheel with most traction, so will power stop on the slipping wheel? And how do know if my rear differential is a "open carrier"? The powertrax part number is 1921-Lock Right Automatic Positive Locking Differential off of JEGS.com. Any help would be great.
thanks everyone,
Jake