Well, I performed a quick search and I was not satisfied with the results. I was wondering whether anyone would be interested in helping me out. You see I'm in the middle of performing a tranny swap, and I would like to know how to distinguish trannies through serial numbers or bar codes. This is what I got so far, but this is of the net so, I'm not sure whether it's correct. 89-90 w5m33-2 npzs awd turbo 91-94 w5m33-2-npxv awd turbo If you would like to contribute, all you have to do is look under your hood, the dsm label with all your vehicle information on it (if it's still clear). Just post the model of the transmission , it's the third row. (assuming you haven't already performed a swap)(don't forget to post the vehicle info). Unless you have a repair manual with all the numbers already in them, that would be alot easier. Thanks for your time.