This guide details the installation of extended differential, gearbox and transfer case breathers on a Toyota Prado. Extending breathers helps prevent water and contaminants from entering the drivetrain components during water crossings and off-road driving.
Problem
The factory breathers are often located in positions where they can be submerged in water, potentially leading to contamination of the differential, gearbox, and transfer case oil.
Solution
Extend the breather lines from the differentials, gearbox, and transfer case to a higher location in the engine bay or another protected area.
- Front Differential: The front differential breather is located under the fuse box. Unclip the Toyota cap, remove the Toyota cap and replace with a 1/4" hosetail adapter. Secure with a hose clamp.
- Rear Differential: Locate the rear differential breather. Remove the factory breather and install a Fuel Line Union (Part # 90404-51026) . Run the extended breather line, securing it to the handbrake cable and fuel lines.
- Gearbox and Transfer Case: The gearbox and transfer case breathers are located near the gearbox. Remove the right-hand side wheel and the rubber flap to access. Disconnect the existing breather lines. Attach extension hoses using joiners. It may be easier to have a workshop complete this if access is difficult.
- Routing: Run the extended breather lines to a chosen location in the engine bay, ensuring they are clear of the DPF and exhaust components. Secure the lines with cable ties.
- Breathers: Mount the breathers to a custom bracket or other suitable location in the engine bay.
Relevant Parts
- Fuel Line Union for Rear Diff: Toyota Part # 90404-51026
- Miniature Gearbox Breathers: 1/4" BSP (e.g., OzHyd.com.au Miniature Gearbox Breathers 1/4" BSP, Code UC-S-680003)
- Hose: Oil-resistant rubber hose (1/4" fuel line is suitable)
- Hose Clamps: Suitable for securing hoses to fittings
- Cable Ties: For securing breather lines
- 1/8" to 1/4" Hosetail Adapters: For connecting different sized breather lines (if needed)
- Tee Piece (Optional): If joining multiple breathers to a single line.
Additional Notes
- Some find access to the gearbox breathers difficult and opt to have a mechanic complete this part of the job.
- Consider adding small fuel filters to the ends of the breather lines to provide additional protection against contaminants.
- Regularly inspect the breather lines to ensure they are secure and not damaged.
- It may be necessary to make a custom bracket from 50x50x3 aluminium angle to hold the breathers.
- Adding a small piece of foam air filter medium inside the breathers can provide additional filtration.
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