I own a '99 Ranger 2WD, 3.0L, 5 speed manual, 3.73 gear ratio. I found a used computer at a salvage yard and bought it as I felt it was worth $20 to have backup. The vehicle it came out of had the same engine/ trans but I did not check gear ratio. The numbers on the computer are similar but not exactly the same. What do I need to look for to make sure the computer I bought is compatible with my vehicle? Thank-you.