certain lockers for certain gears?
 

just curious if you have to buy a certain locker depending on the gears you have in the diff? or can you change your gears after installing a locker in the stock gears?

it depends on the type of locker. Lunchbox style lockers such as lockrite, aussie, ezlocker can use any gears you have in there or any gears you upgrade to, it doesnt matter. Lockers such as ARB and detroit electrac are gear specific.

also in other makes of axles like dana axles you have a differnt carrier depending on the gearset

Huh, who told you that?

Toyota's have no gear/carrier split like Dana/corporate axles do. A 4cyl detroit works with any gears for a 4cyl 3rd, they are not "gear specific". You have your V-6 and 4 cyl diffs, thats pretty much it (for the most part).