I recently bought a 2001 Grand Cherokee with a 4.0 and I found that there is the engine ID number on the side of the block. I have reasons to believe that either the engine, trans or maybe both were changed. I bought it from a woman and she had no clue about anything other than to fill the gas and change the oil when the sticker told her to. The number on the right side of block is 305MX16. I have read that if it starts with a 3 its a 1993 can that be? or could it be a 2003 or would there be more numbers?

Thanks for any help

 

The numbers, at-least in a six digit string, should match-up with part of the VIN else the change would have been documented in service records.