cant seem to find this answer anywhere but is posi or limited slip additive necessary to add when changing gear oil on my 4th gen 3.42 posi rear?

 

yes , from what i have heard from 4wd. people you'll sorry if you don't . they say it's pricey but worth it .

 

can you be a little more clear/specific?

 

Depends on what posi your 4th gen rear has.

If it's an Auburn (97-back), it has clutches, so it needs that expensive $5 bottle of friction modifier.

If it's a Zexel Torsen (98-up), it has no clutches, only gears; so you can buy some commercial real estate or something with that $5 instead of putting it in the rear. Only problem is, it'll take about $2 more of that nice synthetic gear lube, without the clutch friction modifier additive, so stick with only relatively small skyscrapers in your real estate search.

 

and how would one figure out which rear he has?

 

If one did not already know, one would take the cover off and look. If one were smart, one would invest wisely in a little bottle of the substance in question along with a couple of bottles of gear lube before disabling the car, and would either use it, or not, according to the contents of the rear as discovered.

One might also be able to tell by the brakes... the 98-up style uses a little drum system for the parking brake. Not a 100% positive identifier, of course; but reasonably high probability.

 

if one were to have PBR disc brakes with the simple lever type e-brake connectors, could he assume that he needs additive?

 

One could lol i cant do it. Just buy the royal purple gearoil that has it in it. If you didnt need it it wont hurt.

 

hahah thanks for the straight foward answer. will be changing the oil tomorrow