The auto's are pretty bulletproof and seem to never die... If you get bored with the auto a stick is a simple swap.

X2

You can put a gear driven case behind a 340h which is the auto in a 3.0 truck. The adapter is 550$ from inchworm. You will also need a 23spline input on the case. A single 4.7 case would be plenty low enough and could be done for about a grand (550$ adapter + 400$ marlin 4.7 23 spline gear set)

 If you get this truck and wheel it with the stock tranny and t-case report back on how it does. Not alot of people wheel the auto's and I'm curious if the hill climbing issues are exaggerated.

The auto's can also be torn down and rebuilt with simple hand tools as long as you are careful to keep everything in order.