The used car I bought came with 2.5, 2.92, and 3.58 gears plus whatever is already in the car but that's the problem. Is there any way to check what gear is in it without actually having to take it apart? i'm taking it out for the first time to tucson speedway here in arizona and it calls for a 3.90. If that's not whats in the car what would my next best option be?