danoduke

Hey you Z28 experts,

Can anyone tell me what my current rearend gear ratio is? I have a 2000 Z28 LS1 with the stock 10 bolt and automatic tranny. The VIN #2G1FP22G9Y2101844. I'm buying 4.10 ring and pinion gears from MAE Racing and they need to know what I currently have. I don't have a clue, but I think it's in the VIN # if someone has a code book. thanks!

2001NBMZ28

Look at the RPO codes on the driver's door:

GU2 = 2.73
GU5 = 3.23

davey

As far as 0-60, or 1/4 mile times, isn't there about a 2/10th of a second difference in times -- with everything else being equal?

LS1999PewterZ

I did not know that but, I agree with that becasue I just look at my drivers side door and I found GU2 and I have 2.73's

2001NBMZ28

There's a pretty complete list of RPO codes here:

http://www.wiu.edu/users/muwtj1/rpocodes.htm

Capn Pete

I don't know if or how your gear ratio can be determined from the VIN #, but like 2001NBMZ28 stated, GU2 on your door sticker will mean 2.73's, GU5 = 3.23's, and GU6 = 3.42's (only for 6-speed cars). The reason that you need to know what gears you currently have is because there are 2 different carriers for our cars, a 2-series and a 3-series. If you've got 2.73's, you'll have a 2-series, but if you have 3.23's you'll have the 3-series carrier. If you want 4.10's, you need to order them for the correct carrier --- that's why you need to know what you've got (the difference is in the thickness of the ring gear).

danoduke

Found it! Thanks guys. You've been a ton of help. My RPO code shows GU2 so I have 2.73 gears. These gears are great for top end, but I'm looking for more low end grunt. I'll let you know how the 4.10's work out. Again, thanks!

Dan

By the way: I also found a link to check your axle ratio based on the axle stamping in case your RPO tag is missing:

http://www.iroc-z.com/flashlight/how...ivetrain4.html

danoduke

Sorry...that thread should have been:

http://www.iroc-z.com/flashlight/how...rivetrain4.htm

Justin Cruce

is their any other location that has the rpo codes b/c my car was painted and the codes aren't on the drivers door.

rod442

Am I correct in remembering that 2.73 geared cars have a steel driveshaft vs 3.3's getting the aluminum? Look under the car and see what ya got.

Also there is likely a tag on the rearend housing. OR, if you have stock tires and even if you dont, you can check and see how many rpm's you turn at say 50 or 70 and figure it out from there.

Injuneer

Did you check the glove box? If not there, look in the console bin.

Also, you can go here and enter you VIN:

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