How to change your transmission oil in an Inboard engine

Introduction

Keeping your inboard engine’s transmission oil fresh is vital for smooth performance and avoiding big repairs. This guide walks you through the process step-by-step!

📋 Step-by-Step Process

1. Warm Up the Engine

Run the engine for a few minutes to warm the oil (optional, but it helps with extraction).

2. Locate the Fill and Drain Points

Check your manual for the dipstick, fill port, and drain plug. Some use an extraction pump via the dipstick tube.

3. Extract the Old Oil

• With a drain plug, place a container underneath and remove it to drain.
• Without a plug, use an extraction pump through the dipstick tube.

4. Check for Contaminants

Look for metal shavings, water, or a burnt smell in the old oil. Issues may need a deeper check.

5. Replace the Oil Filter (If Required)

Some transmissions have a filter—see your manual for replacement details.

6. Refill with New Oil

• Use a funnel to add the right oil type and amount.
• Don’t overfill—check the dipstick level.
• Get your oil here

7. Run & Check Levels

Idle the engine in neutral for a few minutes, then top off the oil if needed.

8. Inspect for Leaks

Check the drain plug and fill cap for any leaks.

9. Dispose of Old Oil

Take used oil to a recycling center for proper disposal.

🌊 Popular Inboard Marine Gearboxes

Check out these common gearboxes:

• Hurth (ZF)
• Volvo Penta IPS
• Twin Disc
• PRM
• Technodrive (TMC)
• Borg Warner Velvet Drive
• Yanmar
• Masson Marine

Follow these steps to keep your transmission running strong for years!

📋 Oil Types by Gearbox

Always check your manual for the right oil type and amount!