3rd Drive Gear TY856 6MT Ratio 1.761

3rd drive gear for 6-speed manual transmissions with trans ID codes starting with "TY856".  This is the shorter ratio 3rd gear used in USDM STI MY04-06 and all JDM STI.  This gear has 4 holes to engage the synchronizer cone and early (MY01-06) models must update 3rd synchronizer to part number 32650AA160.

Optional REM ISF© (superfinishing) treatment.  ISF is a precisely controlled treatment that reduces surface roughness left from the machining processes thereby improving reliability, reducing friction, and all but eliminating break-in requirements and the resulting swarf.  Ideally, we recommend treating both contacting gears (drive & driven sides) for optimal results.  Adding ISF processing may increase ship time by as much as a week.

Gears may need to be replaced due to gear tooth failure or damage to synchronizer dog teeth.  The peaks of the synchro dog teeth should be sharp and without any noticeable burrs.  Damaged synchro dog teeth due to gear clash or missed shifts will reduce the shift performance and severe damage can cause gear lockout or prevent gear disengagement.

Other possible sources of gear failure are overheating due to lack of oil supply, damage to bearing race surface resulting from bearing failure, or thrust surface wear due to heavy loading and/or lack of lubrication.

Gear Ratio: 1.761

Tooth Count: 21

Manufacturer Part Nos:

• 32275AA550 (USDM STI MY04-06, JDM STI MY01-20) ... 4 hole gear type - MY01-06 requires updating synchronizer.