Originally Posted by auburnJEEP
Well I tried this. RPM at 60mph is slighty above 2K in 5th gear with the auto. How accuate is the tach? I don't have a lot of flat land around here so this is hard to hold steady.
My 2012 with auto and 3.73s looks about like 2000 RPM dead on at 60 MPH. But, you are relying on the accuracy of both the speedo and the tack, so, it can be hard to tell. Yours sounds to close to tell.
You might try holding it in 3rd and then at 3000 RPM:
50 MPH = 4.10
54 MPH = 3.73
As you can see, the ratios are so close it can be hard to tell. I chose 3.73s after much research, over the 4.10s. I don't plan to go bigger than 33" tires, and am not a dedicated rock crawler. 4.10 is mighty deep gearing on the auto 2012 for anything under 35" tires, IMO.