TSX 5th and 6th Gear Parts List

Here is the list of parts that we have found that you need in order to install a TSX 5th and 6th gear. These are longer than the standard RSX or Civic Si gears so you will get better gas mileage. We picked the gears from the 04-08 TSX because they are a touch longer than the 09+ TSX. This will also be the parts that you need if you want to upgrade your 5-speed transmission to a 6-speed. If you have part numbers to add or something we have missed, please email chris@kseriesparts.com and we will get it verified and added.

Message board discussions: Club RSX and Club EP3

Vehicle 5th Gear 6th Gear
02-06 Acura RSX Type-S 0.921 0.738
02-05 Honda Civic Si 0.738 N/A
04-08 Acura TSX 0.870 0.686
Part Acura Part Number
Countershaft 5th Gear 23461-RAS-000
Countershaft 6th Gear 23491-RAS-000
Mainshaft 5th Gear 23580-RAS-010
Mainshaft 6th Gear 23590-RAS-A00
Synchro (You need to order one for each gear you plan on replacing. If you upgrade both 5th and 6th then you need to order two.) 23641-PPP-000
Needle Bearing (You must order this part for the 6th gear) 91103-RAS-003