I don't know how many miles or months you will get out of the seal. We do feel it is made of better material and of a better design than the stock Toyota seal. Of course even a Toyota seal won't make it out your drive way if it's installed wrong, so just make sure you follow these recommended steps to maximize the life of your EcoSeal:
1) Take some 350 grit or so sand paper and rough up the sealing surface on your flange. Seals cannot break into their sealing surface if the sealing surface is as smooth as ice. Make at least 20 rotations of the sand paper on the surface of the flange where the previous seal sealed, making sure there is sufficient roughage for the seal to wear into.
2) Degrease the inner splines of the flange and also the splines on your output shaft, and then apply silicone to the inner splines of the flange. We recommend using Super Gray or Ultra Black. We avoid Orange and Bluesilicon like a plague. You might get away with Red silicon but we consider it inferior to Gray.
3) Always always always apply grease to the inner diameter of the seal before installation. If you forget to do this and have already installed the seal, you can still apply grease with the seal installed but it will be much harder to do so beings you will have a siliconed output shaft right in the way that you don't want to touch.
4) Optionally, you could also add silicone to the back side of the washer before you install the nut, so that the silicone on the washer mates to the flange where the splines are. But this isn't too necessary if the splines were degreased well enough.
As for the oil, no oil will come out assuming your t/case is not over filled and the transfer case itself is nearly horizontal. If any oil does come out, it won't be much, maybe just some residual oil that might run down the housing, nothing a small shop rag can't handle.
Let us know how it works out for ya!
Thanks
Mike
