I just look on the Jeep website where you can download the 2006 Jeep Liberty users manual.
On page 294, it says that if it is a 2WD, it cannot be towed.
But if it is 4WD, on page 295 it desribes the procedure to put the transfer case into neutral which will allow you to tow 4 down. They mention a transfer case lever so make sure yours has it before you tow (or buy). See below:
1. Depress brake pedal.
2. Shift transmission into N (Neutral).
3. Shift transfer case lever into N (Neutral).
4. Start engine.
5. Shift automatic transmission into D (Drive) or manual
transmission into any forward gear.
6. Release brake pedal and ensure that there is no vehicle
7. Shut the engine OFF and place the ignition key into
the unlocked OFF position.
8. Shift automatic transmission into P (Park) or ensure
manual transmission is in any forward gear.
9. Apply parking brake.
10. Attach vehicle to the tow vehicle with tow bar.
11. Release parking brake.
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