Cummins B-Series Diesel Engine Timing Gear Housing 6B, 6BT 5.9 OEM 3963834. IN GOOD CONDITION PLEASE SEE PICTURES. MATCH PICTURES AND/OR PART NUMBER IF LISTED TO MAKE SURE THIS IS THE RIGHT PART YOU NEED. ASK US IF YOU HAVE ANY QUESTIONS OR CALL YOUR LOCAL DEALER. WE STRIVE TO KEEP OUR CUSTOMERS SATISFIED.