: axle ratio



jimtreber
07-12-12, 03:28 AM
The rpo code list for my car has a G80 DIFFERENTIAL, LIMITED SLIP and GU5 AXEL REAR, 3.23 RATIO. Does this mean there are other ratios for the cts or 3.23 is for all?

ncscons
07-12-12, 01:20 PM
Pretty sure 3.23 is for the AWD so the fuel economy is closer to the RWD car. The RWD has a shorter rear end but I can't remember the number. Maybe 3.73?

cawengr
07-13-12, 09:24 PM
The performance option with rear wheel drive is a 3:73 posit reaction rear end

jimtreber
07-14-12, 12:37 AM
Would the 3.73 be for both manual and automatic transmissions?

pinkguy
07-16-12, 06:07 PM
Hi to all
let me throw in, what I have seen in writing.
I got two build sheets, 2011 CTS 3.6DI 6sp-AT Wagon RWD and 2011 CTS 3.6DI 6sp-AT Coupe, RWD
Both had RPO G80 for Limited Slip Positraction.
The Coupe lists RPO GT4 for 3.73 rear ratio
The Wagon lists RPO GU6 for 3.42 rear ratio

pinkguy

KensCTS
11-06-14, 12:35 AM
I have been researching this. Appears to be a 3.23, 3.42 and 3.73. My CTS performance 3.6L has the 3.42. Below is from my build sheet. I believe the GT4 is the 3.73. I am looking to get a used 3.73 off ebay and replace my 3.42. Anyone do this? Drop in replacement? Then I'll have to work on updating the speedo.
GU6 AXLE,REAR,3.42 RATIO 3.42R(GU6)
G80 AXLE,REAR,POSITRACTION,LIMITED SLIP POSITRACTION L/SLIP R/AXL(G80)

ztollon
11-06-14, 09:15 PM
I have been researching this. Appears to be a 3.23, 3.42 and 3.73. My CTS performance 3.6L has the 3.42. Below is from my build sheet. I believe the GT4 is the 3.73. I am looking to get a used 3.73 off ebay and replace my 3.42. Anyone do this? Drop in replacement? Then I'll have to work on updating the speedo. GU6 AXLE,REAR,3.42 RATIO 3.42R(GU6) G80 AXLE,REAR,POSITRACTION,LIMITED SLIP POSITRACTION L/SLIP R/AXL(G80) chances are it will throw off your abs and traction control systems.

SFVetteman
11-06-14, 09:55 PM
chances are it will throw off your abs and traction control systems.I doubt that would happen. I changed out my 2.73 diff with a 3.42 in my '99 Vette and no problems with abs or traction control or anything else. The PCM reads speed at the wheels and while it can be somewhat sensitive to tire diameter it doesn't seem to care what the final drive ratio is.

Bill

everestx
11-06-14, 11:37 PM
There are rumors the 3.91 (1LE) gears fit our carrier.
I've yet to see installed confirmation of this but it is woth noting. Lpe and a few others make them.

1st gear in an auto will be a beast but you will see much higher realized torque as a result

Embassy_
11-07-14, 02:57 PM
GM RPO axle & ratio decoder:

http://www.sierragear.com/gm-rpo-axle-ratio-identification-codes-3/

KensCTS
11-11-14, 02:25 AM
Thanks for the leads. I am looking at the 3.91LPE and thinking I might remove the carrier and have the gears replaced. I'll let everyone know how it goes

glava2876
11-24-14, 08:32 PM
The performance option with rear wheel drive is a 3:73 posit reaction rear end
I have been going through my codes list and my 2014 Performance coupe has GT4, so it came with the 3:73 & G80 positraction .
I have added a Magnaflow cat back and am amazed at how fast this car feels -it is louder and not everyone may like it, but my wife does!

ltdltc
11-24-14, 08:53 PM
Thanks for the leads. I am looking at the 3.91LPE and thinking I might remove the carrier and have the gears replaced. I'll let everyone know how it goes

Is that an option for the 2010+ Camaro?

everestx
11-25-14, 06:07 PM
Yes. 1le is the performance/track package

KensCTS
12-01-14, 12:34 AM
I called LPE, they said the 3.91 for the Camero wont fit the CTS/3.6/RWD, to bad. Best upgrade seems to be the 3.73, I have seen the complete used axle carrior for around $600-$900. Guess I am going to try this.