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Identifying Axle Gear Ratios – 1971 CJ-5 Project

C

chemironsdad

New Member
I’m currently trying to identify the gear ratios for my project, as both the front and rear axle tags are missing.

Initially, I attempted to determine the ratio by counting driveshaft rotations relative to one full tire rotation. I counted nearly five full rotations, which led me to estimate a 4.88 ratio. However, as I am still learning the specifics of gearing, I decided to pull the front differential cover this afternoon to verify the markings on the ring gear.

The ring gear is stamped with the following sequence: DANA 17483 A3B84 438. I am wondering if I might be misreading that "438" or if it indicates a different ratio than the 4.88 I suspected. Additionally, there is a section marked in red that appears to read either M200 or MZ00.

I would appreciate any insights or corrections from the community to help me confirm exactly what I’m working with.
 
Even easier is to look for the tag on the housing.
All the Dana axles came from the factory with a tag, front and rear.
Will only be missing if someone removed it.
On the tag will be the Jeep PN like 924567 (made up number), the ratio like 4.88 or 3.73, and the tooth count like 44-9 = 44/9 = 4.888...
 
Jw60 said:
4.88 wouldn't be a surprise with a v6. Is it hilly terrain where you are?

The common gears are 3.73 and 4.88 for v6. 4.27 and 5.38 for 4cyl.
Click to expand...
You nailed it, it’s definitely hilly terrain where I am, which is why I’m leaning toward the 4.88s. With the V6, I’ve noticed the 3.73s just don't have enough 'grunt' to keep me in the power band without constantly downshifting on the inclines.
 
Jon B. said:
Stamped in the ring gear will be the tooth count of ring and pinion gears: 11-43 or some such combination.

4.88:1 gears are not uncommon in early CJs.

Jon B.
Click to expand...
It’s interesting that the 4.88s were common in the early CJs; it definitely explains why these things feel like tractors in low gear! If I find a different count, like 8-43, I’ll know for sure I’ve got those deeper 5.38s.

Once I get the cover off, should I be looking for any specific wear patterns on the teeth while I'm in there?
 
chemironsdad said:
You nailed it, it’s definitely hilly terrain where I am, which is why I’m leaning toward the 4.88s. With the V6, I’ve noticed the 3.73s just don't have enough 'grunt' to keep me in the power band without constantly downshifting on the inclines.
Click to expand...
I briefly owned a 71 with 4.88's. While offroading was grand, any street driving above 45MPH required an OD, which that one had.
chemironsdad said:
I’m currently trying to identify the gear ratios for my project, as both the front and rear axle tags are missing.
Click to expand...
1775402946589.png
You can see the tooth counts on the far right.
You'll want to drop both covers.
CJ's have a tendency to be molested over the years, culminating in all kinds of mix matched parts. In your case, this usually means extra steps to insure somebody didn't swap out a broken axle with another with a different gear ratio. You can do the "rotate and count" method but it's always better to pop the lids. That also gives you the chance to take a look at the diff (trashlok?) and ring & pinion teeth (27A).
 
And I'll share my 2 cents for the 4:88. My RII came with them stock. I had to replaces the R&P when I swapped in the D30. I do not have an OD. Yes, these gears are GREAT for offroad. I do have a new 225 and 33" tires. It runs fine at 3,200 RPM on the highway.
I don't do much highway driving so the 4:88s are a perfect match for my vehicle.
 
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