2018 Harley-Davidson FLTRXS Road Glide Special — Maintenance & Ownership Guide
Routine Maintenance
Key maintenance tasks to keep your 2018 Harley-Davidson FLTRXS Road Glide Special running reliably.
Engine Oil
Requires approximately 4.9 quarts of 20W-50 oil; check levels frequently due to potential sumping issues on early M8 engines.
Primary & Transmission Lubricant
Separate fluids for primary (approx 1.1 qt) and transmission (approx 1 qt). Essential to monitor for fluid 'transfer' between the two.
Brake Fluid
Uses DOT 4 fluid; ABS-equipped models require a digital technician tool for a full system flush every 2 years.
Common Wear Items
Parts that wear over time on the 2018 Harley-Davidson FLTRXS Road Glide Special and should be inspected regularly.
Rear Tire
The 180/55B18 rear tire typically lasts 8,000–12,000 miles depending on load and riding style.
Drive Belt
Inspect for debris punctures or 'stone pecking' which can lead to premature snapping under high torque.
Brake Pads
Heavy touring weight (855 lbs) leads to rapid wear of front pads, especially when using linked braking frequently.
Popular Upgrades
The most popular aftermarket upgrades for the 2018 Harley-Davidson FLTRXS Road Glide Special.
Stage II Cam Kit
One of the most popular upgrades for the M8 107, significantly increasing torque and improving the exhaust note.
Primary Vent Kit
Solves the 'oil transfer' issue by venting the primary case to atmospheric pressure.
Windshield
The stock low-profile 'Special' windshield is often replaced with a taller or recurve shield to reduce buffeting.
Common Replacement Parts
Parts that commonly need replacing on the 2018 Harley-Davidson FLTRXS Road Glide Special.
Intake Manifold
The factory plastic manifold is prone to warping from heat, causing vacuum leaks; often replaced with aluminum versions.
Oil Pump
Early 2017-2019 M8 oil pumps are frequently replaced with the updated 2020+ OEM or S&S versions to prevent sumping.
Used Buying Inspection Checklist
What to look for when buying a used 2018 Harley-Davidson FLTRXS Road Glide Special.
Transmission Oil Level
If the dipstick is dry but the primary is overfilled, the bike has the 'oil transfer' issue.
Air Cleaner Housing
Check for excessive oil pooling inside the air cleaner, which is a primary symptom of engine sumping.
Clutch Recall (0173)
Verify if the secondary clutch actuator has been replaced; the original part was prone to internal leaks.
Grey Sludge in Primary
When checking the primary oil, a grey/foamy appearance indicates transmission fluid mixing with primary oil.
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