06 in axle code 4.875?

Hey’all:
I’ve always read from various sources that the number “06” in the first gen axle code verified a 3.91 gear ratio. I recently came across this article that said “06” in the axle code could mean the 4.875 gear ratio in the first gen Tacoma.

I’m considering replacing my trucks differentials. I have axle code B06A. How can I be sure I have the 3.91 gear ratio?
I have a MT.

For context, I was considering putting 4.3s in the truck anyway. I am experiencing a bit of loss of power after putting 285/75/16s on the truck. I assume if I had the 4.875 (4.88) I would not be unimpressed/ notice a significant change with 33s.

 

I don't believe Toyota ever offered factory 4.88 gears, especially in a 1st Gen Tacoma. So I think that article is wrong, and your intuition that you have 3.91 is correct.

To be certain, you can pull the diff and count teeth on the ring & pinion gears (should be 43 ring gear teeth, to 11 pinion teeth).

If that doesnt sound fun, then just jack up a rear wheel and spin it (truck in neutral, chock wheels for safety of course). Spin the tire exactly one revolution and count how many revolutions driveshaft makes, it should look like basically 4. The driveshaft should make 3.91 revolutions per 1 revolution of the tire to be exact.