Tires_Smokin

I have a 96 Z28 Automatic

Q: CAN I PUT IN 3.73 Gears if I have an Auto transmission?

I think the standard for a auto Z28 is 2.73?

I wanna go 3.73 so I can be cool like the rest of you with the standard for the SS or Z28. So Whats the standard gears for the LS1 Z28 automatics. I know the SS's have 3.73's. I know that I will run higher RPM if I swap and was curious if any of you auto drivers have swaped the gears and what luck you have had and if any problems arose. I was also wondering If it is alright to swap...would I have to make any other adjustments as far as my car being able to handle the RPM's. Someone told me about the PCM shift points. Would I need a programmer? Whats the RPM limiter? I dont know much about auto's handeling rearend gears...so please someone help me out here with some answers....

Please reply so I can get some info on this. Thanks!

treyZ28

you can put in any gears you want to-

its in the rear differential

you can put in 5.57s if you want

or you can go highway cruiser style with 2.03 or somethign

SS Mark

96 Z28's came with either a 2.73 or 3.23 gear, and 3.42 with a 6-speed. SS only had a 3.23 in auto or 3.42 in 6-speed. No 4th gens came with a 3.73 stock. I have 3.73's in my auto Z. I like them, they do whine a bit but I think thats because who ever had the car before me didnt break them in right, if you do a proper break in they shouldnt make much noise. Also if you have a 2.73 gear you will need a 3 series carrier, if you have a 3.23 you will be fine. You shouldnt need to adjust your shift points, you will just get to your shift points quicker, when you do a cam or something along those lines then you should raise your shift points. You will however need to recalibrate your speedo for the gear change, either use LT1 edit or an hpp3. And you can run any gear with an auto transmission, you can have 4.56's if you want, it has nothing to do with your transmission.
-Mark

Tires_Smokin

I think I have 3.23's or do I have 2.73's?

How do I know...I think I have 3.23's since I have a Z28 right?

SS Mark

A Z28 can have EITHER, 2.73 or 3.23, best way to check is your RPO codes, i believe GU5 is for a 3.23 and GU2 is for a 2.73.
-Mark

JUNKHEAD52

To tell if you have 2.73 or 3.23 look in your glove box and look for a gu3 or gu5 code if gu3 you have 2.73 if gu 5 you have 3.23.
Gary
95Ta

Tires_Smokin

Thanks for the info...looks like I have 3.23's. So where can I get some info of reading all those numbers thats on that sticker in my glovebox?......

Thanks again guys!