The part number is wrong on Subaruparts.com. Double click on the hypoid gear set (first part on the list) and it takes you to a page where it shows $0 for total and a red X next to quantity, indicating the part may not be available. Notice the bulletin number next to the part number (PT280397). Now type in 38100AA551 in the "add another part" box. Notice the same bulletin number. That bulletin explains that 38100AA170 has been changed to 38100AA551.





Dave