Mustang Gear Ratio to RPM Comparison Chart

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Use this chart if you're wondering what gear ratio is currently in your Mustang, or looking to change your Mustang's rear gear ratio. By comparing your rpms when cruising at 65mph, you can figure out what gears you have. Anyone upgrading to a different gear ratio, you can see what effect this may have on gas mileage. The transmission tag identifier will help you if you're unsure what transmission is currently in your Mustang.

Mustang Rear Gear Ratio to RPM Chart

Estimated RPM Range for Highway Driving (~65MPH)

Anyone who’s purchased a used Mustang before knows how annoying it can be to figure out if the previous owner changed the rear gear ratio or not. Sometimes, you know they were changed but have trouble identifying what ratio the new gears are. Below, we have mapped out the usual suspects when it comes to aftermarket gear ratios. If you do not see the RPM for which you are reading at 65MPH for your particular transmission you can safely assume by going with whatever ratio of gears falls between the provided sets.

This chart will also give people who are thinking about changing their Mustang’s rear gears a look at the increase in RPMs they will see for each ratio. Note that the smaller the gear (smaller gears have higher ratios – 4.10s are SMALLER than 3.73, ect.) the more RPMs. Higher ratio gears can actually increase fuel efficiency around town but will use more fuel when driving on the highway, and vice versa.

Transmission Type

3.55 Gears

3.73 Gears

4.10 Gears

AOD + AODE (automatic transmission)

1800 RPM’s

2000 RPM’s

2300 RPM’s

4R70W (automatic transmission)

2000 RPM’s

2250 RPM’s

2350 RPM’s

T5/T45 (manual transmission)

2000 RPM’s

2250 RPM’s

2350 RPM’s

TR3650 (manual transmission)

1900 RPM’s

2250 RPM’s

2350 RPM’s

T56 (6 speed manual transmission)

1600 RPM’s

1800 RPM’s

2150 RPM’s

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