So, I decided to replace my 24 Metanium DC 71 factory gear set with brass to see what's the difference, ordered 2 of each

(Drive gear 1021Q) and Pinion gear (1006L), both are same set for 18 Bantam and 20-23 Metanium and are also compatible

with 24 Metanium DC 71, got the parts in and immediately noticed something was off with the pinion gears I've received.

Drive gears are fine and identical but look at the picture of the pinion gears below.

 

Both are packaged as 1006L, the one on the left was dated 2018-03-07 and the one on the right

was dated 2024-03-19. Called Shimano CS, sent them these pictures and the gentleman I've talked to told me he'll have to do some digging

to find out what's going on then will let me know. I already kind of know what's going on but have to confirm it

for myself and luckily, I was right. The pinion gear on the right is a revised version of the OG BNT5593 which is now 1006L

for the reels mentioned above, it was revised/shortened to fit the 24 Metanium DC, the one on the left matches the pinion for my 18 Bantam/20-23 Metaniums, while the pinion on the right matches the OG pinion of my 24 Metanium DC 71.

 

The only thing I did not try is to install the shorter pinion to my 18 Bantam and 20-23 Metanium to see if they

would work but makes me think it will, the taller pinion on the other hand will not work with the 24 Metanium DC IMO.

 

I wonder why Shimano did not assigned a new part number for this shorter pinion but instead still called it with the same part number.

 

Anyway, just sharing my findings and hopefully explained the whole clear enough.

I don't think the pinion height makes that much difference w/ clutch travel, since it shoulders in bearing #28 - there's nothing but air around the spool spindle (long) end above it.  

 

When I bought a used Ryoga for salt niche, I completely rebuilt it because it came from the salt and the copper shields on all the magseal bearings were oxidized black (noteworthy, they all spun well, but I also replaced them all).  

I learned on TackleTour the '21 Basara Hyperdrive brass gears could replace the alloy gears, and I swapped those - difference on gear teeth profiles is shown by the  old pinion laying across the frame.  

I did give up drag clicker making this swap, but could never hear one in coast wind, anyway, and I can feel drag pay through the rod.  This reel also swaps spools with my other 34-mm floating-spool Daiwas.  

@bulldog1935 Very good point and I thought about the same things, but we have to realize that the 24 Metanium DC is slightly built different than the 20-23 non DC, handle side plate was modified to fit both spool and pinion bearings with a small amount of gap in between to give room for the end of the pinion from hitting the spool bearing under the tension cap, basically if you remove the tension cap on the Metanium DC what you'll find is the spool bearing instead of the pinion bearing, on 20-23 Metanium, typically you can see the pinion in action sliding through the pinion bearing when pressing the thumb bar.

 

All I can say and prove at this point is the OG pinion gear for the 20-23, 18 Bantam is taller than the one for the 24 Metanium DC while using the same Part#.

 

Hopefully Shimano CS call me back soon for more info to really find out, I was going to send Bantam1 over at TT a message but the site was down yesterday, but I will pretty soon.

It still seels likely that newer part number works with both newer and older reel, and keeps it simple for Shimano to continue supporting them all with one part.