Diff fluid
http://www3.towerhobbies.com/cgi-bin...RCH=diff+fluid
I'd suggest 7000wt for front and center diffs, 5000wt rear. They come from the factory with a little grease in them. Clean 'em out and put in the fluid.
Lubricant:
http://www3.towerhobbies.com/cgi-bin...?&I=LXATCH&P=7
degreaser for cleaning bearings:
http://www3.towerhobbies.com/cgi-bin...&I=LXSEL1&P=ML
If you don't have a good set of hex drivers you'll need some. Buy quality first. MIP make good ones. You'll need 1.5mm, 2.0mm and 2.5mm.
IMO, you're over-paying for that Venom battery, but you apparently have the means, and prefer ordering everything from Tower. That's cool. But you can save considerable money if you consider alternatives. At least well-known alternatives. Some call it "cheap Chinese junk", but in my experience, they're just as good as anything else. Cheap servos can be dodgy, but batteries, motor systems and chargers, if you know the right brands, work great and are considerably cheaper.