Hi,

Maybe you heard of it, but there is this little RC truck that looks amazing.
High and low gear, dif locks, portal axles, waterproof, etc...

Here is a video in action (you'll find hundreds others) :
Youtube Video

And here is a video detailing the mechanic. Go straight to 10min for the most interesting part :
Youtube Video

Looks fun !

@minikeum trx4 is very nice imo, but a bit too much to possibly go wrong for my liking. keep it simple. 2speed trans and selectable diff locks may be the ticket for some, personally just give me a good usable single gear and full time locked diffs. i do dig the portals though and would love to have them for my truck.