Totally different pinions too
Some are cut at different angles like your two
Some are cut a little concave/convex whatever it is called
End of day replace a D pinion is easy enough
O pinion you need puller tbh
Replace pinion if you can or feel it's too worn
Check how it meshes with the bevel you are using
Did it buy a new motor, rip open a couple of knackered neodym motors
Swap out crapped out armatures with a 22tpa ferrite one
Thus making up a cheapo torquey motor for just a bit of time
But really, new motors start from £25/£30 why bother going nutz
Use whatever you got 16-22tpa 30k to 22k aprox for most builds
With neo magnets if possible and whatever meshes with bevel
Get a couple of old motors and rip apart if you are bored to make up one or two new revamped ones if you like, new pinion/brushes but a new SHS HT will work well for £28 too
Up to you how much time you got on your hands and if you can be bothered
