2021+ 850 Switchback Assault 146 Chaincase Fluid Replacement

For more information on tools, read the Tools and Fasteners Guide.

This video will outline the pump and front cover methods that can be used to change the chaincase fluid on a Polaris Matryx Switchback Assault 146 with a 850 engine. Always wear safety glasses and nitrile gloves when servicing your Polaris snowmobile. 

1. Place the sled on a flat, level surface.

2. Set the parking brake.

3. Clean the area around the fill plug. Placing a rag under the fill plug will help catch any escaping fluid.

4. Remove the fill plug with a 6mm Allen socket and set aside.

5. To extract the fluid using the pump method:

• Using a floor jack or appropriate lift, safely elevate the front of the snowmobile.
• Insert the tube of the suction device into the fill hole. Direct the hose toward the bottom front area of the cover, away from the chain and sprocket.
• Extract the oil using the suction device.
• Safely lower the snowmobile to fill the chaincase.

6. To drain the fluid using the front cover method: 

• Remove the right side panel by turning the three quarter-turn latches. Pivot the panel away from the sled and pull out to remove.
• Remove the fastener on the lower-right side of the console with a T40 TORX® socket.
• With a pliers, remove the push rivet securing the lower right portion of the console. 
• Remove the push rivet underneath securing the right fender to the footrest.
• If equipped with a battery, remove the battery and bracket. The full procedure can be found in 2021+ 850 Switchback Assault 146 Battery Removal and Installation. 
• Remove the two fasteners securing the lower fender to the chaincase with a T40 TORX® socket.
• Place a drain pan underneath the chaincase. Placing a rag in the bottom of the drain pan will help prevent the splashing of fluid.
• Loosen but DO NOT remove the three lower chaincase cover fasteners with a 10mm socket.
• Carefully pry on the cover tab and allow the fluid to drain completely. DO NOT insert a screwdriver or pry bar between the cover and chaincase.
• Once complete, reinstall the three cover fasteners and torque to 11 ft-lbs (15 Nm). 

7. Clean any dirt or debris from the fill plug.

8. Inspect the O-ring on the plug and replace if necessary. 

9. Fill the chaincase through the fill plug hole until fluid reaches the bottom threads and begins to spill out. The fluid capacity is 10.5 ounces (310 ml). A 1-quart bottle of Polaris Synthetic Chaincase Lubricant is part number 2873105.

10. Reinstall the fill plug and torque to 48 in-lbs (6 Nm). 

11. Clean any residual fluid off the vehicle and dispose of the used fluid at your local recycling center.

12. If using the front cover method, continue with the following steps:

• Reinstall the fasteners securing the lower fender to the chaincase. Torque to 36 in-lbs (4 Nm). 
• If needed, reinstall the battery bracket and battery. Connect the positive cable first. 
• Reinstall the push rivet underneath the console.
• Install the push rivet on the lower right portion of the console.
• Reinstall the lower console fastener. Torque until fully seated.
• Reinstall the side panel by inserting the upper tab and pivoting in to engage the lower tab. 
• Latch the three quarter-turn latches to secure the panel.

Looking for information on adjusting drive chain tension? Read 2021+ 850 Switchback Assault 146 Drive Chain Tension Adjustment.

For more information, see your authorized Polaris Dealer. To find a dealer near you, use the Dealer Locator.
Maintenance tips, procedures and specifications can be found in your Owner's Manual.
To find diagrams and replacement part numbers, use the online parts catalog.

TORX® is a registered trademark of Acument Intellectual Properties, LLC
YouTube® is a registered trademark of Google LLC

Unless noted, trademarks are the property of Polaris Industries Inc.
© 2022 Polaris Industries Inc.