gear ratio help needed

I search and did the Spin the tire once and count the # of time the drive shaft spins. Marked with soap stone its 1 tire circle to 1 3/4 drive shaft. im lost, i did it have a dozen times, one tire off the ground, both/ holding one still... Thanks looking for an 8.8

I dont have the money for new diff fluid/seal 2day as i just did $602 in ball joints on my tow rig and the jeep

10/90 build so 1991 4.0 auto xj

You have 3.55 gears. IIRC, get both tires off the ground, rotate one & let the other spin on its own. JIM.