Ron is right, the Right Stuff from permatex is the best out there, not only is it a sealant, but it is also like a glue... out of all the crappy I have done, that stuff by far holds the best, especially when you have the chance of pealing your diff cover back and developing a slow leak...
as for fluid, I used to run synthetic (redline),,, but I have found it to be a waist,, for as much much crap as you get into if you just change it regularly, you can do 4 changes for the price of synthetic. I usually try and change it every 4 big events, or at least every six months,,, and you will find, that that usually it will be pretty contaminated,,, little bit of water from the deep crossings, (not from bad seals, just that water is thinner than oil and a few drops can get past the axle seals) Also, you will find that the condensation that developes from an axle getting really hot, to being cooled by a puddle or mud will contaminate to...
Also if you have the d-35 with the rubber plug, you will be getting water in there left and right... Just use the cheap stuff... (when the axle gets hot, then you hit the water, the steel will actually constric and cause you to suck water right in, so I have heard somewhere :wink: )
If you are sticking with the d-35, they do have covers that swith to a threaded plug... that will make a huge differance...
Use the good synthetic if you have a locker, or a Rubi that requires it :wink: (towing is a reason as well) but you can get a good 80W140 for cheap now to...
