Maintenance

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Here are some common maintenance procedures. I'll try to expand this and add more videos. If you need more help, the best thing to do is post in the Ryobi 48V Mowers Subreddit. Alternatively, you can post in the Ryobi 48v Riding Mowers Facebook Group.

Transaxle / Gearbox Oil Change

RM300

Ryobi didn't specify a service interval or procedures for the RM300 transaxle. It's intended to be a sealed unit without a vent, but changing the transaxle oil is still possible. If you remove the right rear tire, there is a fill hole on the side of the transaxle. Opening this with an alen wrench, you can then use a fluid extractor syringe to put most of the oil out. Add in the same amount of oil back in the same hole. I believe it uses the same gear oil used on the RM480.

RM480

Ryobi suggests a 100 hour interval for changing the transaxle oil. They do not account for time, but the oil can absorb moisture from the air even when it's not being used. They also don't account for the break-in period. So I usually recommend the following:

• First oil change: After 50 hours or 1 year

• Normal use: Every 100 hours or 2 years

• Heavy use: Every 50 hours or 1 year

  • Regular use of the mower to tow / carry / pull heavy loads or on very steep terrain

The manual specifies using 250 ml or 8.5 oz (1 cup + 1 tablespoon) of GL-4 80W/90 gear oil.

GL-4 oil is hard to find and intended for manual transmissions with brass components. Most people use GL-5, which is widely available. I suggest using a synthetic oil since they tend to perform better, especially in cold weather, and the price isn't very different. Most synthetic gear oils will be 75W/90. Gear oil typically comes in 1 liter containers, so a single bottle will be good for 3 oil changes with some remaining.

Here are a few gear oil options. I use Red Line, but I think you will get similar results with any of them.

ZT480 / ZT540

Ryobi didn't specify a service interval or procedures for the gear reduction boxes on the zero turn mowers. However, these are vented and will absorb moisture over time in addition to normal wear and tear. They do have drain plugs accessible behind each rear wheel and the vent can be unscrewed and used as a filler hole. I have not yet measured how much oil is needed, but will update this section when I have more information. I believe it uses the same gear oil used on the RM480.