Before pulling the transmission out of the vessel, execute these high-priority diagnostic steps to isolate simple hydraulic or mechanical faults. 1. Checking and Maintaining Hydraulic Oil
Once the internal planetary array is exposed, lay the components out sequentially on a clean surface. Inspect the following critical friction and pressure surfaces: tmp gearbox workshop manual top
If the 8-bush input is seized due to rust, experts at Thamesway Marine Products suggest cutting a small access hole in the housing to apply lubricant and leverage the flywheel directly. 2. Inspection for Wear Before pulling the transmission out of the vessel,
A "top" inspection of the gearbox involves removing the top cover to inspect the selector mechanism and internal gears. When the cover is off, look for: Pitting on the gear teeth. Metallic debris in the bottom of the casing. Play in the input and output shaft bearings. When the cover is off, look for: Pitting on the gear teeth
When prepping for a partial overhaul, utilize this part matrix to verify components before ordering from your parts distributor: Assembly Component Direct Drive Setup Reduction Box Setup Wear / Tolerance Checks Part TM 12090 Part TM 12090 Check for groove scoring on input flange Output Shaft Seal Part TM 12020 Part TM 12436 Inspect output flange seating surface Transfer Shaft Seal Part TM 12436 Inspect shaft concentricity Gasket & O-Ring Kit Part TM 12470 Part TM 12470 Always replace 100% on casing split Neutral Brake Pad Part TM 12016 Part TM 12016 Check lining thickness Oil Filter Assembly TM 12009 / TM 12773 TM 12009 / TM 12773 Varies by MK II or MK IV variant Critical Field Troubleshooting
A full overhaul requires specific replacement parts to ensure the integrity of the hydraulic seals and mechanical drive. Component Type Part Number / Requirement Seals the output shaft for direct drive units. Gasket Kit Includes essential O-rings for pressure integrity. Brake Pad Neutral brake pad for stopping shaft rotation. Oil Filter TM 12009 / 12773 Models differ between MK II and MK IV versions. Step-by-Step Workshop Procedures 1. Removal and Disengagement