Cool! Then clean up is a snap, as I described. Just don't let anything get "crusty".
In addition to the minor maintenance I mentioned above, the other things to check on every so often are the tranny, diff, and motor.
Don't be intimidated by the thought of taking stuff apart, it's not as complicated as you might think. The only thing that is kind of scarey the first time is the thought "what if I don't remember what screw goes where?" First off, you should have your vehicle manual for reference. Then, the first time anyway, have enough space to work where you can lay out all the parts and screws as you take them apart and have them grouped together in their sub-assemblies.That way you won't confuse what screw goes with what. Additionally, you can draw outlines of the sub-assemblies on paper and place the screws on the drawing in the appropriate place. But really, once you do this a couple times, you get very comfortable with it and you don't have to be so elaborate.
The gears in the tranny need grease once in a while. I like TrakPower Waterproof Gear Grease. Has anti-sling properties. You will have to remove it from the chassis probably as a sub-assembly that includes the motor, motor plate, and tranny. Un-do the screws that hold the tranny to the motor plate, then open the tranny. You probably have three gears in there: the Input gear, the idler gear, and the diff. You probably also have two more bearings in there, that the diff rides on. (The other gears have bearings too, but the ones for the diff get the dirtiest.) While you're in there, take the bearings out and check them as you did the others. Clean out all old grease, and certainly any dirt.
Now is the time to check the diff. Ball diffs require more maintenance than gear diffs to work properly, and I don't have experience working with those, so I cannot guide you there. But if it's a gear diff, open it up and clean it out as you did the tranny case. (If there are shims, thin little washers, behind the little gears in the diff, be careful not to loose them) If the diff is designed for using silicone diff fluid, refill with fresh fluid. If not, use the same grease as the tranny. If you're greasing it, don't pack too much in there, or the diff will "lock" and will act as a solid axle. When you re-assemble the diff, turn it with your fingers to check for proper diff action and smoothness. Give all the tranny gears a good coating of grease, and re-assemble the tranny, cleaning off any grease that may have squeezed out.
For the motor, yours is brushed, so nothing really to do there but blow it out with compressed air. But if you have a brushless motor, you could take it apart too for cleaning. The rotor has bearings it rides on that need cleaning and lubing, and the inside can collect a good deal of dust. If possible, remove the motor bearings and clean them as you would the others. On yours, once the brushes have worn out, the motor is shot and needs replacing. Good time to upgrade to Brushless and Lipo.
Once your motor is clean and the diff and tranny lubed, you can re-install the motor onto the motor plate, and this is when you set your "mesh", the interface of your pinion and spur gear. Too tight, and you can ruin your motor, too loose and you can strip your spur. Best way to get it right every time is to use the paper trick:
Take a strip of plain printer paper and fold it in half. Stick the strip in between the pinion and spur gear and firmly hold the pinion to the spur as you tighten the motor mount screws. The space taken up by the paper, once removed, will give you perfect mesh. Then re-install the motor/tranny sub-assembly back into the car. DONE!
You should have an infra-red thermometer. If you don't have on, get one. Duratrax sells one for $24. Use it to monitor your motor and ESC temps. I check temps during, and after every run. When you know your well-lubed car usually has a motor temp of 130F, and one day you see it's running over 150F (assuming same outdoor temps) then you should conclude that maybe one or more of your bearings need attention. In general, ESCs run about 125F, motors in the 130-150F range. WIth brushless motors, anything over 180F you risk damaging the motor. And don't forget, gearing affects motor temp. Your car came with a pinion gear of a size that puts the car's gearing in the "sweet spot". (Or it should have) Going up a tooth or two on the pinion size will raise the motor temps, and conversely a smaller pinion will lower it. (Going TOO low, however can also increase motor temps, and ESC temps)
Hope that helps ya. Sounds like it's complicated, but it's not, really.