CFMOTO Front & Rear Gearcase Oil Change

Why This Job Gets Skipped

Gearcase oil has no dipstick on most CFMOTO machines and no warning light. Nothing tells you it is old, and the machine drives exactly the same on twelve-month-old gear oil as it does on fresh. So it gets forgotten, and then a front differential that would have been fine on a 250 millilitre fill of gear lube turns into a rebuild.

The interval is 100 hours, 1,000 miles, or 12 months, whichever lands first, halved if you ride in water or mud. Water is the specific enemy here. Gearcases sit low and breathe through vents; a river crossing or a deep mud hole can pull water past a seal, and water in gear oil turns it into a grey emulsion that stops protecting anything. If you ride wet, change it more often and look at what comes out.

What Oil to Use

CFMOTO specifies SAE 80W-90 GL-5 gear oil for both the front and rear gearcases across the current range. GL-5 is the important part, it is the additive package rated for hypoid gears under high tooth pressure, which is exactly what a differential is. Do not substitute GL-4 because it was on the shelf.

The transmission is a separate fill and a different oil. On the machines that have a separate transmission, CFMOTO calls for SAE 75W-90 GL-5. On the U10 Pro and Z10 the transmission and rear differential share one case, also 75W-90 GL-5.

Capacities by Model

Note the CForce 600, where the front case takes more than the rear. Every side-by-side in the range is the other way round. If you are working on an ATV after years of side-by-sides, it is an easy one to pour wrong.

The Procedure

The front gearcase on most of these machines cannot be level-checked. The filler port sits above the correct oil level by design, so there is nothing to see when you open it. The only reliable method is to drain it completely and refill with the measured amount. Measure into a graduated bottle before you start rather than trying to judge it going in.

1. Park on level ground, in Park, engine off and cool enough to touch.
2. Put a drain pan underneath. On the front case you will usually need to jack the machine and pull a front wheel to reach the bolts.
3. Remove the filler bolt first. If you cannot get the filler out, do not remove the drain, or you will have an empty case and no way to fill it.
4. Remove the magnetic drain bolt and washer and let it drain fully. Look at what comes out: metallic paste on the magnet beyond a light fuzz, or a milky grey colour, means water or wear and warrants a closer look before you refill.
5. Clean the magnet, fit a new crush washer, and torque the drain bolt to spec. That is 18.4 ft-lb (25 N·m) on most of the range and 25.8 ft-lb (35 N·m) on the Z10.
6. Pump in the measured quantity of 80W-90 GL-5, refit the filler bolt to the same torque, and wipe the case down so you can spot a leak later.
7. If you removed a wheel, finger-tighten the nuts then torque diagonally — 81 to 88 ft-lb (110 to 120 N·m) on the bigger machines, 52 to 59 ft-lb (70 to 80 N·m) on the CForce 600 and UForce 600.

What Bad Gear Oil Looks Like

Healthy used gear oil is dark and smells strongly of sulphur, that is normal for GL-5 and not a fault. What you are looking for is a milky coffee colour, which is water contamination and means a seal or vent needs attention, or heavy metallic sludge on the drain magnet, which means gear or bearing wear. A light grey fuzz on the magnet is normal. Chips or flakes you can feel between your fingers are not.

If you find water or metal, stop and get it looked at before you put a lot of miles on it. We can help diagnose it — call 330-806-0728.