The 2 MAIN numbers that relate to PARTS acquisition are the CHASSIS (VIN) and/or the ENGINE# . . .

It's always BEST to give a COMPLETE Chassis and/or Engine number when ordering parts, unless you are SPECIFICALLY asked for the LAST 6 numbers . . .

There are times when you will be asked for a PS PUMP, STARTER, ALTERNATOR, ELECTRICAL or A/C COMPONENT Manufacturer and TRANSMISSION or DIFFERENTIAL numbers, as well as PAINT and INTERIOR TRIM codes.

The LAST 6 numbers are the broken down into "up to" and "from", relating to their order of manufacture. In the EPC, you will see terms like (A = along with) meaning that the part has been superceeded and an ADDITIONAL part is required.