Im about to buy a 95 z28 from a pal and i need to know if the computer needs reprogrammed since he installed 3.73s. His the stock 2.73 gearset took a crap and locked up on him while he was driving down the road, the day he installed the 3.73s he suspected the tranny was shot because he has to go thru every gear to get to drive but said it does fine once its there. Im in Iraq right now and cant take a look at it but i dont wanna go ordering a new tranny when its jus something simple, anyone know what could possibly be wrong and know a fix?

I asked him some questions in an email and this is what he sent me, hopefully it will help...

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Nothing was wrong with it till the gears took a crap. To start off 3:73
gear ratio. Once I got the gears in the car and went to drive it everything
was fine. I got to the stop sign at the end of the road, and when I went to
pull it went to shift to second and it popped out gear it seemed like. So I
went ahead coasted to the side, put in park took a look under the car
everything is fine. Got back in and put it into drive and it didn't even go
into gear, put it in reverse went into gear, so I went ahead shifted down to
1st gear went into gear. Took off put it into drive when fine, but when I
came to a stop I would have to shift it back down to 1st to take off. It
doesn't really seem like it is slipping, it just seems like the detent
is gone for the shift mech. Because if you manual shift it, it runs great,
except if you are in drive and you go to get on it and kick it down to
passing gear it pops out of gear and you loose everthing, but you just knock
it down to 1st let it engage and you can put it right back into drive and it
runs fine. That is pretty much what it is doing right now...

 

Yes, it must be reprogrammed with an automatic, because the speed reported to the PCM will be off. The PCM shifts by speed. It might not cure what it is now doing, but it is the right place to start.