Notes: 138831 SYNCHRONIZER ASSEMBLY 506 D90 1^ / 2^ is original CARRARO product. 138831 SYNCHRONIZER ASSEMBLY 506 D90 1^ / 2^4 is commonly used in transmissions/axles/engines 134998, 137394, 137394, 134998, . if you have any questions please do not hesitate to contact us via Whatsapp +17275652849