Axle gearing question 3.54??

[XXLMJ]

I have a dana 44 in the rear of my 89 MJ 2wd. I'm in the process of doing a 4wd conversion. My rear axle tag says 3.54 on it. I thought most front axles were 3.55? So is 3.54 something hard to find or will a .55 work?

[jpdocdave]

same thing

[XXLMJ]

Cool, is it the same thing or is it so close that is doesn't matter.

[JeffK]

close enough it don't matter

[Pete M]

Yup. The ratios come from dividing the number of ring gear teeth by the number of pinion gear teeth. Because axles come in different sizes, there are different numbers of teeth in them. For example, the Dana 30 will have 41 teeth on the ring gear and 10 teeth on the pinion, giving a 4.10000 ratio. The Dana 44 on the other hand has 45 teeth on the ring gear and 11 teeth on the pinion, giving a ratio of 4.09090. the Ford 9": has 37 and 9, giving 4.11111 Round them off and you get 4.10 and 4.09 and 4.11.

[HOrnbrod]

I have a dana 44 in the rear of my 89 MJ 2wd. I'm in the process of doing a 4wd conversion. My rear axle tag says 3.54 on it. I thought most front axles were 3.55? So is 3.54 something hard to find or will a .55 work?

 

Don't bet the farm on the rear axle tag. It's best to verify the ratio by the stampings on the r/p gears or physically count the teeth on each and divide. :cheers:

[Pete M]

Or turn the axle shaft and count the pinion rotations. If one axle shaft remains still, rotate the moving one twice. If both shafts move together, then go around just once. (and if the other axle shafts rotates in the opposite direction, you'll need to hold it still) If the pinion rotates 3 and a half times, it's 3.54.

 

But if you're buying a used axle, it's always a good idea to pull the cover and inspect for damage. :thumbsup: