John...the gearing is easy to find out, and there are a couple of ways to do it.

Easiest.....Crawl under the rear of your rig, and look at the rear dif. There will be a tag on the left side of the cover with some numbers on it. The ratio will be on there...it will be something like 3.07, 3.55 or 3.73.

Or.....jack a tire up, and rotate the tire once while counting the number of times your driveshaft turns. That will be your ratio.

Randy Halvorsen
98 Explorer XLT
99 F150 4x4
90 BMW 735i
00 BMW 323i
47 CJ-2A