Kohler Silent Fill Toilet Valve Kit GP1138930 — Quiet refill, adjustable fill-rate inserts (gray shank)

If your Kohler toilet tank is noisy, slow to refill, or you want to maintain original performance after a repair, this authentic Kohler fill valve is engineered to match factory specifications. Designed by Kohler engineers, the kit preserves your toilet’s intended operation and helps protect product warranty when replacing worn or damaged fill components.

How does this valve make tank refills quieter?

The valve uses Kohler’s Silent Fill design to reduce turbulence and mechanical noise as water flows into the toilet tank. That smoother water path and controlled flow minimize the splashing and vibration that cause typical refill noise.

• Engineered internal flow passages for reduced noise
• Stable valve seating to prevent chatter during refill
• Designed specifically for Kohler toilet geometries for optimal quiet operation

Can I adjust the fill rate and save water?

Yes — the kit includes multiple fill-rate inserts so you can tune the refill volume and speed to your toilet’s needs. Switching inserts lets you find a balance between fast tank recovery and lower water consumption without changing the entire valve.

• Several inserts included to fine-tune flow rate
• Simple insert changes allow custom water-use optimization
• Maintains reliable flushing performance when set correctly

Will this part fit my Kohler toilet?

This fill valve is compatible with most Kohler Class 5 toilets, but fit is determined by the tank shank color. If the tank shank is grey, GP1138930 is the correct part; if it’s black, Kohler’s GP1083167 should be used instead.

• Designed for Kohler Class 5 models
• Check the tank shank color: grey for this kit, black for GP1083167
• Simple swap-in installation for compatible tanks

What maintenance or cleaning should I avoid?

To keep the finish and components intact, do not use abrasive brushes, scouring pads, or harsh scrubbing agents on the valve or cap. Gentle wiping with a soft cloth and mild detergent is sufficient for routine cleaning.

• Cap color may vary without affecting performance
• Avoid abrasive cleaners and pads to protect surfaces and seals
• Follow Kohler Genuine Parts guidance to preserve warranty coverage

Who is this for? Homeowners, plumbers, and maintenance professionals who own or service Kohler Class 5 toilets and want a direct-fit, factory-designed replacement fill valve. Choose this genuine Kohler kit when you need a quiet refill, the ability to adjust water fill rates, and the assurance of parts engineered to Kohler specifications. Confirm the tank shank color before ordering to ensure correct compatibility and maintain your toilet’s original performance and warranty support.