Jack up one rear wheel and turn the driveshaft. The spider gears will double the wheel speed so your 3 3/4 turns of the driveshaft will actually be approximately a 7.50:1 ring and pinion ratio. To get an accurate count of driveshaft revolutions it would be necessary to roll the truck forward in a straight line and count the driveshaft turns for one turn of the rear wheels..
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
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