Wasn't sure if this had been posted before but I thought I'd share.
Thank you for contacting the Jeep Customer Assistance Center.
In regards to your email, the different letters and numbers have
The first number is the country of origin.
The second letter is the vehicle make.
The third number is the vehicle type.
The fourth letter decribes car (restraint system) truck (gross vehicle
The fifth letter decribes the vehicle line.
The sixth number decribes the vehicle series.
The seventh number decribes the body style.
The eighth letter decribes the engine.
The nineth number is the check digit.
The tenth number or letter is the year of the vehicle.
The eleventh letter is the assembly plant.
The 12 through 17 numbers are the series numbers.
Thanks again for your email.
Customer Service Representative
Jeep Customer Assistance Center