With your valve stem straight down, make a chaulk mark on you r driveshaft.
Have someone drive truck straight ahead one tire rotation. Count number of
turns of driveshaft until the valve stem is straight down again. If mark has
gone around just over 4 times, it's a 4.10. Three and three quarters turns,
it's a 3.73. Just under3 and one half turns, a 3.42. Just over 3 turns, a
3.08. Quicker than tryin to cipher a code!