what number in the vin determins what gears are in the car? like 2.73(stock) = 3.23 = 3.42 = iv heard some cars came with a 3.42 in a auto...my cars a auto.

Also how would i determine what gears i have without taking rear girdle off? i am 98% pos i dont have stock 2.73's because iv used some calculators and im way off.
Thanks

 

Forget about the Vin for any options on the car. Check the RPO codes for the info and if those are not available, just pull the cover.

 

There's nothing in the VIN that would tell you the rear axle ratio. As noted in the post above, the 3-character RPO code on the build tag is going to tell you that.

Might want to add info about the year of your car..... people could help you narrow it down a bit more.

 

I'm going to go out on a limb and guess that you have a 1993-2002 Trans Am.

If this is the case, you have 2.73s or 3.23s. Only M6 cars came with 3.42s.

As a general rule, if you automatic shifter has a selectable "1" option, you have 3.23s. If you only have a "2" option, you have 2.73s.

To be sure, though, look at the RPO codes. These are the series of three-character codes on a sticker on the driver door (the back of the door where the latch is).

The following codes were used for 1993-2002 F-body cars:

GU2 - Axle, Rear 2.73 Ratio
GU4 - Axle, Rear 3.08 Ratio
GU5 - Axle, Rear 3.23 Ratio
GU6 - Axle, Rear 3.42 Ratio

And if you see the G80 code, you have a limited slip differential.

 

heh yeah i saw that online searhing yesterday...looked at door quick but didnt see any GY # ill look today. im at school right now. Thanks