Automatic Transmission Slipping, Hesitating, or Shifting Rough? LIQUI MOLY Pro-Line ATF Cleaner LM20224 — Flush Deposits & Restore Performance Before Your Next Fluid Change

Dirty, deposit-laden automatic transmission fluid is one of the most overlooked causes of rough shifting, hesitation, and premature transmission wear — and a simple fluid drain without a pre-flush leaves the worst of those deposits behind. LIQUI MOLY's Pro-Line Automatic Transmission Cleaner is a highly effective pre-service flush formulation that dissolves and suspends stubborn varnish, sludge, and debris from inside the transmission before the ATF drain, so your fresh fluid goes into a clean system. When old ATF is changed without a pre-flush, accumulated deposits remain on valve bodies, solenoids, and clutch packs — contaminating the new fluid immediately and continuing to cause shifting problems. ⚡ The professional-grade ATF flush used in repair shops before every quality transmission service. Part LM20224 is the genuine LIQUI MOLY Pro-Line formulation that gently cleans without attacking rubber seals or plastic components, restoring optimum shifting performance and extending transmission life.

❓ Is This the Right Product?

This is the correct choice if ALL of the following apply:

• ✔ Your vehicle has an automatic transmission (not CVT or manual)
• ✔ You are performing or scheduling an ATF fluid change
• ✔ Your transmission uses standard ATF (compatible with most ATF types)
• ✔ You want to maximize the effectiveness of your fresh ATF by flushing deposits first

Not sure? Send us your vehicle make, model, and year — we'll confirm compatibility before you order.

🔧 Signs Your Transmission Needs a Pre-Flush Clean

• Rough, jerky, or delayed gear shifts — especially 1–2 or 2–3
• Transmission hesitates or slips when accelerating from a stop
• ATF is dark brown, burnt-smelling, or overdue for a change
• Shifting has become noticeably worse over time despite no mechanical fault
• Previous ATF change didn’t fully resolve shifting complaints

✔ If these symptoms match, a pre-flush with LM20224 before your next ATF change is the most effective step to restore smooth, responsive shifting.

✔ In most cases, combining a Pro-Line flush with a fresh ATF fill restores normal transmission behaviour immediately after the service.

📦 Product Details

• Part Number: LM20224 (also referenced as 20224)
• Type: Pro-Line Automatic Transmission Pre-Service Flush / ATF Cleaner
• Volume: 1 Litre
• Coverage: 1L treats 6–9 litres (1.6–2.4 gal.) of ATF
• Brand: LIQUI MOLY
• Compatible With: Most automatic transmission fluids; ideally paired with LIQUI MOLY Gear Tronic ATF (Part# 7917)
• Safe For: Rubber seals, plastic components, and all internal transmission materials
• Use: Professional repair shop use recommended

⚙️ How to Use

Skill Level: MODERATE — 15 minutes active + 10 minutes idle time. With the transmission at operating temperature, add the full 1L of Pro-Line ATF Cleaner directly to the transmission fluid. Lift the vehicle and let the engine idle for approximately 10 minutes. Shift through all gear positions once or twice. Switch off the engine, then drain the ATF and replace the transmission filter. Refill with fresh ATF to the correct level. For best results, use with the LIQUI MOLY Gear Tronic system.

✓ Compatibility

Compatible with most automatic transmissions using standard ATF. Suitable for use with the majority of ATF specifications including Dexron, Mercon, and equivalent fluids. Safe for use in vehicles from most major manufacturers including GM, Ford, Chrysler, Toyota, Honda, BMW, Mercedes-Benz, and Volkswagen Group vehicles with conventional automatic transmissions. Contact us to verify compatibility with your specific vehicle before ordering.

💡 Pro Tip