I have a 2003 2500hd 6.0l and i blew up my posi the other day. all the research i have done today say's i have a 10.5 14t ff, but when i looked it up on pirate 4x4 i found a thread that said i had a aam 10.5. but im still gonna say i have a 14t because yukon gear and axle claims it to be a 14t. but anyways back on topic. i was looking to get a detroit locker to replace my blown posi but after a bit more reading i found that you cant install the locker in a 14t with posi. is there a version that you can or a way you can make it work? i really want a detroit locker in my truck.

Yeah, start with a non G80 carrier. Typically, Detroits don't replace the GM carrier as it is beefy enough.

AAM made the old-style 14bolt as well as the new one.

AAM is just the old axle division of GM that was spun off as an independent company.

As already mentioned, it's not that you can't install a Detroit in that axle if it came with a factory posi, just that the Detroit does not replace the entire carrier but rather just replaces the side and spider gears (think Lock-right) and thus only works in an open carrier. All you need to do is swap in an open carrier first.