See how a rear gear swap changes highway RPM. Compare popular Mopar ratios side by side before making the switch.
Most traditional 727/904 automatics are 1.00 in third gear. Enter 0 for slip to see theoretical RPM; real non-lockup converters may run higher.
At 70 mph with 245/45R17 tires
Engine RPM at 70 mph, using the same tire and transmission setup.
Compare highway cruising RPM and see how fast each ratio travels at your target engine speed.
| REAR GEAR | 50 MPH | 60 MPH | 70 MPH | 80 MPH | MPH @ 3,000 RPM |
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On mobile, swipe the table sideways to see every speed.