when to shift

In general: Shift early. Earlier than you would shift any other car.

The engines are not designed to run at high rpm. They like the slower pace. Unlike other cars they don't produce any more power at high rpm - all they do is scream. And they drink a lot of gas.

So, shift early. Take it easy. Relax.

As explained before, you will have to start in 2nd gear when on pavement.

Shift into 3rd between 10 and 15 mph (max)
(acceleration in 3rd will be slow - be gentle on the gas)

shift into 4th between 30 and 35 mph (max) under NO circumstances drive faster than 35 mph in 3rd! **
(acceleration in 4th will be slow - be gentle on the gas)

When downshifting remember that
2nd is like 1st
3rd is like 2nd
So, when coming from the highway and turning into the parking lot of the supermarket don't downshift into 2nd - it is too low. In addition to that you might get some gear grinding.

** The Jeep is especially vulnerable at high rpm. Starting at around 35 mph in 3rd gear the transmission will deploy rattling noises - once you hear that noise, the synchro assembly is about to fall apart. At 40 mph in 3rd gear you will have destroyed the transmission.