23778954 Lower Gear | Genuine Volvo Penta Part

🔧 Product Description

Genuine Volvo Penta lower gear, part number 23778954, listed in the Marine Propulsion group. It transmits drive through the gearcase, taking engine torque and delivering it to the propeller shaft at the ratio and direction the drive is built for. Volvo Penta publishes no fitment, dimensions or assembly detail against this number, so check it against the parts list for your own engine before ordering.

⚙️ Key Features

• Genuine Volvo Penta lower gear
• Marine Propulsion group
• Drive-transmitting component within the gearcase
• No fitment or dimensions published against this number — check it against the parts list for your engine

🔌 Function

Transmits drive through the gearcase, taking engine torque and delivering it to the propeller shaft at the ratio and direction the drive is built for.

⚠️ Common Signs of Failure

• Whining, growling or howling from the lower unit that changes with load or direction
• Metallic particles, glitter or a bronze sheen in the drained gear lubricant
• Chipped, pitted or wave-worn gear teeth, or a contact pattern hard over to one edge of the tooth
• Clonking or shudder on engagement, or excessive play felt at the propeller shaft
• Milky or water-contaminated lubricant, which usually means a failed seal has already started the gears rusting

🛠️ Service Notes

• Lower gears are supplied and worked on as a matched set — do not mix a new gear with used mating gears, and keep matched bearing pairs together
• Shim values must be re-established whenever gears, bearings or housings are changed; set tooth backlash and check the tooth contact pattern against the specification for your drive rather than reusing the old shim stack blind
• This work needs the correct Volvo Penta special tools and measuring gear; without them the gear set cannot be set up correctly and will not last
• Work clean, inspect the housing bores and bearing seats, and renew the seals and O-rings that are disturbed
• Fill with the specified lubricant to the correct level, then run the drive gently under light load before working it hard, and check the lubricant for metal afterwards

📦 Condition

• Genuine Volvo Penta part
• Brand new
• Supplied in original or equivalent packaging