* NSG-370 5-speed manual: This was a very common manual transmission.
* AX-15 5-speed manual: Also a frequent manual option.
* 42RE 4-speed automatic: This was the automatic transmission option.
To know for sure which transmission a *specific* 2001 Jeep Wrangler has, you'd need to check the vehicle's documentation (owner's manual or vehicle identification number (VIN) decode).