How to Find Gear Ratio on Rear Differential 2009-14 Ford F-150

What's up, guys? I'm Andy from 1A Auto. In this video I'm going to show you how to find your gear ratio. If you need any parts for your vehicle, click the link in the description and head over to 1AAuto.com.

One way to figure out your gear ratio is you're going to count the splines on the ring gear, so I just mark it. Take a marker, mark it, and then count around. So one, two, three, four, five, six, and then all the way around you're going to go, and we have 41 splines on this ring gear. And then you're going to count the pinion, so do the same on the pinion. Just make a mark and count. We have 11 splines on the pinion.

We're going to take this number, so 41, and divide it by this number, 11, and it comes out to 3.727, and you're going to round up, so it's going to be 373s. That's your gear ratio for this. This set-up, at least.

Another way to check if you have the pinion out is to look on the pinion. This actually has it stamped right on there, 373s, so we know that's the gear ratio for this vehicle.

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