Anyone taken apart rear differential on X5 2003 3.0?

[Bmwe5320023.0]

Counted teeth on my old x5 2002 ring gear, 41 teeth. Counted teeth on the "new" pinion gear, X5 2003, 10 teeth.
So I'm pretty sure the teeth on both differentials are the same, since both differentials are the same as well, 4.10 ratio.
I understand your explanation why the snap rings are different sizes. So basically same differentials can have slight variations.
The only thing I don't understand why now, is why the numbers on the two ring gears are different. Both have 41 teeth looks like.
The differential I purchased from X5 2003 has these letters and numbers on the pinion gear. Not sure what they mean?

[Henn28]

Originally Posted by Bmwe5320023.0

Counted teeth on my old x5 2002 ring gear, 41 teeth. Counted teeth on the "new" pinion gear, X5 2003, 10 teeth.
So I'm pretty sure the teeth on both differentials are the same, since both differentials are the same as well, 4.10 ratio.
I understand your explanation why the snap rings are different sizes. So basically same differentials can have slight variations.
The only thing I don't understand why now, is why the numbers on the two ring gears are different. Both have 41 teeth looks like.
The differential I purchased from X5 2003 has these letters and numbers on the pinion gear. Not sure what they mean?

If the tooth counts/ratios are the same, and the new ring gear bolted up to your diff carrier then I think the numbers don’t matter. Im no expert, but I think the gears gears must be the same dimensionally. Perhaps the different numbers are different suppliers, or factories, etc.?

Testing backlash isn’t too difficult. You just need a dial gauge which are cheap on Amazon.

Edit...you need a dial guage and some time to watch youtube videos! RacingDiffs has some good ones on building diffs, and the guy who does "spank ranch garage" videos on youtube does good work too and super entertaining. He's got a thrasher 3Series drift car that he did a quick diff rebuild for that is entertaining, and is worth a watch from a learning standpoint.

My dial gage was cheap and worked well. The magnetic base can be attached to the diff case, or a metal workbench table.