what kind of RPMs should I be running?

[denisb]

I just bought a new to me 2004 sport trac V6 5speed auto and I'm turning about 2.7 to 2.8 on the RPM at highway speeds of 60 to 70 MPH, It seems a little high, but it's my first Explorer, so just curious?

Denis

 

[JoshC]

that doesn't sound to far off, but you could also have 4.10 gears.

 

[denisb]

Any way of knowing what kind of gears I'm running without taking the rear end appart?

 

[MountaineerGreen]

You can check your axle tag, it should have the ratio on it. Its a stamped piece of metal held on by one of the bolts that holds the cover on.

 

[JoshC]

There is also a tag on drivers door or door jam that has an axle code. Somewhere on here is a list of the codes and what they mean.