3rd Drive Gear TY856 6MT Ratio 1.591 REM ISF:No 715315 (Complete Kit)

715315 (Complete Kit)

Exhaust gaskets should also be replaced whenever the system is disassembled and the gasket has any significant time or mileage on it

AP3-SUB-003  (MY08-14 WRX & STI / MY07+ EJ255 Legacy/Outback/Forester)

The ECU compares the rear oxygen sensor signal to the front oxygen sensor signal to determine if the catalytic converter is operating efficiently

3rd Drive Gear TY856 6MT Ratio 1.591 REM ISF:No 715315 (Complete Kit)3rd drive gear for 6 speed manual transmissions with trans ID codes starting with "TY856". This is one of the two taller (longer) 3rd gear ratios used by Subaru and is for USDM STI MY19 21 (and MY18 RA). Also used in some European market applications. 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