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Gear ratio problem (weird)

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canadianwheeler

NAXJA Forum User
Location
canada
I picked up a d35 with 4.11's today for dirt cheap. I checked the tag and it says 4.11 605387-3. I ran the number on dana's web site and it says all my info in correct. Then i tried the wheel spin and counting the drive shaft rotations and somthing weird came up. For every full turn off my wheel i only get just over 2 turns of my drive shaft???? Shouldnt i get just over 4 ? Does that mean is has like 2.11 gears?

I must be missing somthing here.....
 
canadianwheeler said:
I picked up a d35 with 4.11's today for dirt cheap. I checked the tag and it says 4.11 605387-3. I ran the number on dana's web site and it says all my info in correct. Then i tried the wheel spin and counting the drive shaft rotations and somthing weird came up. For every full turn off my wheel i only get just over 2 turns of my drive shaft???? Shouldnt i get just over 4 ? Does that mean is has like 2.11 gears?

I must be missing somthing here.....
Click to expand...

The rotation of the spider gears. Turn both wheels one full turn together.
 
The most straight forward way is to have both wheels off the ground, mark the wheels (both, and the input), turn the input enough times to get the wheels to make one full revolution. Just count how many times you had to turn it and you've got your ratio.
Usually the wheels will turn together, but you mark them to make sure.
 
You have to turn both wheels at the same time, or if you only spin one double the number and thats your ratio. sounds like its the 4.10's if the pinion spun just over 2 times.

you can also pull the dif cover and count the number of ring gear and pinion teeth.
 
It makes perfect sense. Pull the diff cover and look at the gears (you should change the fluid anyways, so this is no extra work) while you do your test. You should see how the assembly works, and it should make sense.
 
Also, seeing the assembly and seeing how it works makes it MUCH easier to diagnose noises and things when something goes wrong. (like when you blow a spider gear)
 
i think theres a confusion here over what 4.10 really means.. i dont really know either. is 4.10 the ratio of pinion teeth to ring gear teeth, or does 4.10 mean "one rotation of the tire is 4.10 rotations of the pinion"?
 
It's both the ratio of teeth and the # of driveshaft turns to axle turn.

Having the open diff and not turning both axles together halves the number. With a locker one could turn one side and both would go equal times in the same direction

And by pulling the cover and counting gear teeth, one might get to inspect the condition of them and confirm the ratio.
 
stupidfast said:
i think theres a confusion here over what 4.10 really means.. i dont really know either. is 4.10 the ratio of pinion teeth to ring gear teeth, or does 4.10 mean "one rotation of the tire is 4.10 rotations of the pinion"?
Click to expand...

It is a gear ratio and that means exactly what it says; the ratio of one gear to another. Since tires and driveshafts aren't gears why would they be involved in a gear ratio. To determine gear ratio you divide the number of teeth on the drive gear into the number of teeth on the driven gear. A common scenario for a 4.10 gear ratio is for the pinion (drive) to have 10 teeth and the ring gear (driven) to have 41 teeth. 41 divided by 10 is 4.10
 
60thAnivrsryXJ said:
It is a gear ratio and that means exactly what it says; the ratio of one gear to another. Since tires and driveshafts aren't gears why would they be involved in a gear ratio. To determine gear ratio you divide the number of teeth on the drive gear into the number of teeth on the driven gear. A common scenario for a 4.10 gear ratio is for the pinion (drive) to have 10 teeth and the ring gear (driven) to have 41 teeth. 41 divided by 10 is 4.10
Click to expand...


That makes sense
I would think that different tire diameters would skew any numbers you get?
I would just count the gears, that’s what I did to check mine
 
Ok I give in a little; tires and driveshafts can be involved because they are what connects to the gears (1 driveshaft rotation = 1 pinion rotation, and if both tires are turning the same speed then 1 tire rotation = 1 ring gear rotation). But when you get down to the bottom of it its the gears they we are really describing when we talk about a gear ratio.
 
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