i d@mn near lost my B-W 9-bolt today when it RAN OUT OF FLUID!!! i just replaced the diff cover seal and have not noticed it leaking at all. but today i hit the clutch to start it and as it was rolling backwards i began to hear the gears meshing together, so i looked under the car and much to my dismay the diff was SOAKED!!!!! so tomorrow i get to replace it again. a couple of questions for all you x-perts out there, first one sounds really dumb and really is just a reassurance of correctness to myself, do i use RTV on this seal? if so, do i use the red kind or what kind do i need? i used the red stuff last time. my next question is, ive scanned the forum and i noticed that it is controversial whether or not to use posi additive to this rear end, should i? i did last time and have noticed no problems at all, is there any harm in this?

 

if t he faces of the housing and the cover are ok you need to use no silastic !
as for t he additive ,personally i use it in mine BUT GM in aus (the 9 bolt rear is still current in aus )
reccomends that the only time you need to use the additive is if the rear end "chatters"

 

I use Redline's light-weight shock-proof (smurf blue in color) in my 9 bolt. I've not had to run any additive.