The chaincase is an integral part of a snowmobile’s drive system and houses a chain and two sprockets that transfer power from the transmission to the track. Its secondary function is as a gear reduction system, allowing the track to spin at a lower speed than the engine. The snowmobile’s transmission connects to a smaller gear in the chaincase connected by chain to a larger gear within the case that turns the track and propels the sled.
A chaincase serves a similar function to other chain drive systems, like those found on many motorcycles and ATV/UTVs, however a snowmobile chaincase contains the chain drive components in a sealed and removable case. To protect the track’s critical drive components from moisture, corrosion and wear, the chaincase is a closed lubrication system that requires regular oil changes to function correctly.
Chaincase oil breaks down primarily from pressure, heat, contamination by metal shavings from the internal gears and chain, and water from the environment. Snowmobile manufacturers recommend changing chaincase oil annually or every 2,000 miles. It is considered best practice to change the chaincase oil after the riding season is over, to prevent moisture from sitting in the chaincase all summer. The typical snowmobile chaincase requires about eight to 11 ounces to refill and is complete when “filled to spill” or overflowing from the fill hole.
Changing Chaincase Oil
Gather the following tools:
- Oil-drain pan
- Ratchet and correct-sized socket
- Funnel (if necessary)
- Chaincase oil
- Drain the chaincase oil
Locate and remove the drain plug. Examine the oil as it drains. If you notice a silver color, it means the chain and gears have produced metallic particles. This is normal. A chain and gears will generate some metal. However, failure to change the oil yearly allows metal particles to circulate and lead to accelerated wear. That’s why it’s vital to change chaincase oil yearly.
- Replace the drain plug
Once the oil has drained completely, ensure the gasket on the drain plug is undamaged and replace the plug. Check your owner’s manual for torque specifications. If there are none, tighten snugly and avoid over-tightening.
- Add new chaincase oil
Now it’s time to install the new chaincase oil. Remove the fill plug. The location of the fill plug varies depending on your snowmobile. Check your owner’s manual for the location. Position a rag beneath the fill hole to avoid spills. Fill the chaincase. Use a funnel if necessary.
With the sled used in the video demonstration below, the chaincase reservoir is full when oil runs out of the fill hole. Some snowmobile manufacturers specify the amount of oil to install, so check your owner’s manual for the proper quantity. Replace the fill plug and wipe down the area.
That’s all there is to changing snowmobile chaincase oil. It’s an easy maintenance practice that will help you get the most years and best performance from your sled.
Is Chaincase Oil Specific?
Modern snowmobiles and ATVs require extreme-pressure lubricants engineered to meet the high-temperature and high-load demands. Some users believe they can substitute alternate oils in their chaincase to reduce costs.
However, automatic transmission fluid does not contain the extreme-pressure additives needed for enhanced wear protection, leaving gears and chains vulnerable. Likewise, automotive gear lube is too thick for proper chain and gear lubrication in powersports applications, impairing circulation and leading to increased wear and decreased efficiency. Finally, unlike thinner motor oils, snowmobile chaincase oils are typically SAE 75W.
AMSOIL Synthetic Chaincase & Gear Oil is a 100% synthetic formulation that resists shear and chemical breakdown better than conventional fluids, providing superior protection and performance for enclosed chains and gears found in snowmobiles, ATVs and other similar equipment.
It is formulated with extreme-pressure additives for increased wear protection that helps extend chain and gear life and it repels water to inhibit rust and oxidation. Its low pour point ensures superior low-temperature starting and reduces drag to deliver maximum power through the frigid depths of winter. It is engineered for use in all snowmobile chaincases and costs less than most original equipment manufacturer (OEM) recommended chaincase oils.
Video transcript: How to Change the Chaincase Oil in Your Snowmobile
Hi. I’m Len Groom. Welcome to Tech Tips. Today we’re talking about changing the chaincase oil on your snowmobile.
This is something that I recommend you do yearly because the oil can get used up, and a chain and gears does make metal. I also recommend that you do this at the end of the season. That way, when you get your sled out in the fall, it’s ready to go. Here’s a few steps on how to get that done.
The first thing you need to do is locate the drain plug so that you can drain the old oil out. Remove the drain plug, and take a look at the old oil as it comes out of the snowmobile. In this case, you can see that it’s silver. Silver means that the chain and gears has made some metal, and the oil is used.
Replace the drain plug. Make sure that you get it tight. Make sure that the gasket is good. At this point, we need to put the new product into the chaincase.
So remove your fill plug. The location of the fill plug can vary from snowmobile to snowmobile. On this model, it’s located right in the footwell. It’s a good idea to put a rag down.
Then we’re going to go ahead and fill the chaincase. Now, with this sled, we know it’s full when the product starts to run out of the fill hole. That indicates that we’ve reached the max level. We can go ahead and replace the fill plug, wipe down the area, tighten it up.
On some snowmobiles, there’ll be a designated amount of oil that you’re going to add to the chaincase. I recommend that you check your owner’s manuals for proper quantity. Here’s a classic example of why you want to change that chaincase fluid on a yearly basis. If you noticed when it was draining out of the snowmobile it had that silver tint to it.
That indicates that there’s some metal in there. That’s perfectly normal. A chain and gears is going to make some metal. What you don’t want is you don’t want to leave it in there year after year and that metal starts to snowball and you can see wear start to occur.
It can lead to a costly repair. So we recommend that you change that on a yearly basis. And, when you change it, I recommend that you use the AMSOIL Chaincase and Gear Oil. There you have it.
Thanks for watching. We’ll see you next time.
This article is part of our Snowmobile Oil and Maintenance guide. See every article in the guide.
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David Hilgendorf is an AMSOIL Technical Writer who develops content for automotive, powersports and industrial audiences. His work includes technical data sheets, magazine articles, blog posts, white papers, product literature and application guidance. Hilgendorf works with engineers, laboratory personnel and technical specialists to communicate lubricant testing, product performance, maintenance practices, metalworking fluids, grease, motorcycles, marine equipment and industrial reliability.
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