How can I find out what rear end gears I have?
I'm believe I have 2.73's since I have an A4, but am not sure.

The drivers side door does not have the label on it with the codes. ( Previous owner had someone back up into the door, so he completely switched it out.)

Any other way I can find out?

 

Next time you go for a drive, check where your RPMs are at a given speed. Then go to http://www.f-body.org/gears/ and plug in your tranny with the chart. It'll tell you what RPMs you'll be at for a given speed.

Example -
A4 with 3.23's = 31 MPH @ 4,000 RPM in 1st gear
A4 with 2.73's = 37 MPH @ 4,000 RPM in 1st gear

Hope this helps...

 

OR..........cruising at 70 - 75 mph (in overdrive) is around ~2000 RPM!

As well, I "think" that 3.23 cars have an aluminum driveshaft, whereas 2.73 cars have a steel driveshaft (although I think I've heard stories of opposite scenarios..........but those have probably been either factory screw-ups, or maybe cars switched from one to another before change of ownership, then the new owner says "...but I've got an aluminum DS with 2.73's??" .

 

I once hurd something like a 2:73 car wont allow you to shift into 1st where as a 3:23 car will.

 

I think that has to do with some sound or emission issues. I haven't heard that realated to gears.


Thanks alot guys.

 

That's with LT1 F-bodies................with LS1 F-bodies, you can shift into 1st regardless of 2.73 or 3.23.

 

Hey I think that helps me as well. I have 2002 Z28 M6 that I bought used about 2 weeks ago with 8900 miles. The previous owner did some mods and I've figured out a coupla of them but didn't think about the rear end. I turn about 1900-2000 rpm in 6th gear @ 70 MPH According to that chart I figured about 4.11 gears... does that sound right?? Also is that desirable or not??

Thanks