I was checking my gear ratio by spinning the tire and counting revs of driveshaft. On the rear if i turn the tire once it basically gives me a 4.10 ratio. When i did the front i had to turn the tire twice to get the same ratio why???

I know its not possible for front to have. 2.0 gear

 

Did you have the hubs locked?

 

Unlocked would give him nothing in the front. Both wheels have to turn together front and rear to get an accurate reading. With one turning backward you would get nothing, and with only one turning (with one on the ground) it would divide the reading in half. You have to mark the opposing wheel to make sure it turns a full revolution in the same direction.

 

I had one in the air spinning the other on the ground. Both hubs had to be locked or driveshaft would not spin.

 

This is your answer, with one spinning and one stopped on the ground because of the differential the ring gear spins only once for every 2 rotations of the spinning tire. When you did the rear I bet you had both tires off the ground and with a posi that both turned equally.

 

Yes sir it has a locker in the rear. I rotated the tire and it turned a little more than 4 turns. I figure 4.10 close enough which is what i was told it had. The front gave me 4 turns but with two rotations of the tire.

 

It is actually easier to turn the wheel twice and then look at the pinion/yoke than it is to jack it up on both sides and deal with exact revolutions on both sides. (unless you have a locker).

 

Sounds right, FWIW I got a suggestion for you if you want to be sure. Need to do it times 10. 10 ring gear rotations should get you 41 driveline rotations, the point being that it's much easier to for example tell the difference between 41 turns(4.10 ratio) and 43 turns(4.3 ratio) then 4.1 turns and 4.3 turns. So on the rear with the locker jack up both tires and turn them 10 times and count rotations. On the front with an open differential, leave one tire on the ground and turn the other 20 times, this will turn the ring gear 10 times.

 

That's too much trouble. On an open rear end you can turn one wheel twice and the yoke will spin a little over 4 times on a 4.10 ratio rear end which is 4 plus 1 tenth of another turn. A 4.56 ratio would be a hair over 4 1/2 turns on the yoke etc.

 

Be good enough if you like but ratios can vary by small amounts that still have a bad effect. 4.11 and 4.10 no problem, 4.11 and 4.30 problem. With a variation of only 0.29, a non exact measurement of tire rotations and driveline rotations can easily be missed leading to an assumption that a 4.30 is a 4.11. Thus my suggestion, not that hard to turn it a few more times.

 

A 4:30 would be quite obvious since it is a third of a turn vs a tenth of a turn for the 4:10/11.

 

It seemed like with two turns of the tire the driveshaft turned almost excactly 4 times. But it has a little slop in it. The rear turned excactly 4 and a hair with one turn. But the rear has a locker and also seemed tighter. No slop.

 

You have to start turning the wheel when the slop is gone (watch the yoke). The slop is a combo of spider teeth, splines, gear backlash, bearing wear, etc, all adding up and it is normal.