Keep the accessory drive belt properly tensioned with the Dayco Accessory Drive Belt Tensioner Assembly 89478. Positioned to serve the alternator, fan, water pump, and main drive, this tensioner applies steady load to the accessory drive belt so it stays snug on the pulleys and keeps those engine accessories turning. It installs as a direct-fit replacement for the listed heavy-duty applications, including the 1995-1999 Freightliner FL80 and the 1999-2005 Peterbilt 320.
- Spring-loaded tensioner arm: maintains consistent tension on the accessory drive belt to help limit slip and flutter.
- Integrated pulley: guides the belt as it routes over the accessory drive.
- Assembly-level replacement: supports the alternator, fan, water pump, and main drive accessories per the catalog position.
Signs the original tensioner may need replacing include belt squeal or chirp, belt slippage, or a rattling, worn pulley. If a failing tensioner is the cause, this unit replaces it. Diagnose the belt system before ordering.
Interchange: 38504 · 49501 · 45820 · 45837 · 910015A · VKM910015 · 910015. Manufacturer part number 89478 · Dayco brand.
Fitment: 2005 Autocar LLC. Xpeditor WX; 2005 Autocar LLC. Xpeditor WXLL; 1996 Blue Bird SHL All American; 1996 Blue Bird SHL Commercial; 1996 Blue Bird SHL TC2000; 1996 Blue Bird TC2000; 1996-1997 Freightliner FL50; 1995-1997 Freightliner FL60; 1995-1997 Freightliner FL70; 1995-1999 Freightliner FL80; 1997-2001 Freightliner MT35; 2001 Freightliner MT45; 1999, 2001-2002, and 2010 Freightliner MT55; 2002-2003 Orion Bus Orion VII; 1999-2005 Peterbilt 320. See the Buyer's Guide tab for the full list.
This part cross-references / interchanges with the following part numbers:
38504, 49501, 45820, 45837, 910015A, VKM910015, 910015
