When changing oil this week, I also changed the HCM filter. You need to change the engine oil at the same time as there is a considerable amount of oil in the HCM housing. The filter is buried under all the tupperware. You have to remove the large side cover to get to the bottom bolts. I initially took the small panel off down by the brake thinking that I could remove the filter through that access. Not a chance. For you DIYer's out there, it isn't a terrible job. Just make sure you organize the fasteners that you remove so you can get them back in the correct place.