I realize that the major difference is that the 07-09 transmission had the straight cut 5th and the 2010-2013 has a helical 5th. What I find peculiar is:

The part# for the HD trans for a 2009 was 33035-09 which is superseded by 33162-07A. It is kinda weird that the supersede goes to an earlier year base number (09 to 07).

Furthermore, the replacement part for 2010-2013 is 33166-10A. If the helical 5th was a "fix" for the 2009 trans, why doesn't the replacement for the 07-09 go to the 10-13 part?

The SE catalog lists a 6 spd for 10 and up touring bikes (32228-14).

Does anyone know why a 2010 trans would not work on a 2009?

 

Well, in case anyone is interested, I called Horny Toad where I usually order my parts and asked about this. They hit the original 33035-09 part number (listed as obsolete)...which supersedes to 33162-07A which it also listed as OBSOLETE with no supersede! Don at Horny Toad checked HD-tech-net and it indicated that it upgrades to 33166-10A which is the helical cut 5th gear.

 

Another update - 33166-10A IS NOT AN ASSEMBLED TRANSMISSION. Jon said it comes with the parts - unassembled.

 

The other change that was made was the diameter of the mainshaft in 08, 09-2014 should be the same.

 

2011 Crossbones:
I checked my transmission oil level today and it shows full when hot, BUT the oil looks almost clear and very thin. Not easy to see on a chrome/polished dip stick. For 85W 90 gear oil and my experiences with differential oils on my trucks it should look like black and thick. WTF is up with this?

 

Depending on what brand of oil you put in, it stays pretty clean in there compared to auto trannies. I run the 85-140 synthetic in mine and it looks like water on the stick. Feels like gear oil though and that's what counts.

Griz