3.55 Ratio R&P tooth count 39/11 & 46/13

[Jed]

I have 2 D30 front axles both have a tag stating 3.55 ratio. The axle I'm pulling (factory axle) has a 46 tooth ring gear and 13 tooth pinion.... 46/13 = 3.538 ratio.
The axle I'm going to use to replace the factory axle has a 39 tooth ring gear and 11 tooth pinion..... 39/11 = 3.545.

First time I have run across this issue... Anyone have any experience with this?

 

[Blaine B.]

Suposidly it will work just fine if they are within 1% of eachother

3.538 / 5.545 = 0.9987%

So basically 1% it should be fine.

 

[89xj]

46-13 is for the dana 30, 3.54 gearing, but the 39-11 is also 3.54 but not for a dana 30. maybe for the dana 35 or dana 44

http://www.precisiongear.com/dana30r.htm

either way, they are both 3.54/3.55 and are the same ratio. just like there is not enough difference between 4.10 and 4.11. it depends on the diameter of the ring gear, thats why i dont know why there would be 2 different ring gear teeth count for the d30 unless one is a reverse cut and one is a standard cut. is one of them lp and one is hp?

 

[Johnnie Walker]

With the ratios they will work.

 

[Jed]

46-13 is for the dana 30, 3.54 gearing, but the 39-11 is also 3.54 but not for a dana 30. maybe for the dana 35 or dana 44

http://www.precisiongear.com/dana30r.htm

either way, they are both 3.54/3.55 and are the same ratio. just like there is not enough difference between 4.10 and 4.11. it depends on the diameter of the ring gear, thats why i dont know why there would be 2 different ring gear teeth count for the d30 unless one is a reverse cut and one is a standard cut. is one of them lp and one is hp?

They are both hp. The differential that I pulled out of my 87 has 46-13 R&P. The other differential was pulled from an old 85 Cherokee and has the 39-11 R&P. I did lay the ring gears on top of each other and they are the same diameter... Just seems strange the same gear ratio and differnet tooth count... According to what everyone is saying, I just need to stick it in and hammer down. Thanks for the input!
BTW, I'm not familiar with a front D35??

 

[Jed]

The 39/11 is in and working fine.