105 Series Gearbox Oil Capacity – Your Complete DIY Refill Guide
The manual gearbox in a Toyota Land Cruiser 105 Series (H150F/H151F) has an oil capacity of approximately 2.2 to 2.7 liters (2.3 to 2.9 US quarts). The definitive method for a DIY mechanic is to fill the gearbox until the fluid is level with the bottom of the fill plug opening.
That grinding sound or a stubborn refusal to shift smoothly into gear—if you’ve driven a high-mileage 4×4, you know the feeling. It’s your Land Cruiser’s way of telling you something needs attention, and often, the culprit is the lifeblood of its transmission: the gear oil.
Neglecting this crucial fluid is a fast track to expensive problems, especially in a rig as capable as the 105 Series. Understanding the correct 105 series gearbox oil capacity is more than just a number; it’s about preserving the legendary reliability you depend on, whether you’re on the daily commute or miles from civilization.
This guide will give you the confidence to tackle this essential maintenance task yourself. We’ll walk you through everything from identifying your specific gearbox to filling it with the right amount of the right oil, ensuring smooth shifts and a healthy transmission for years to come.
Why Getting the Gearbox Oil Capacity Right is Non-Negotiable
Think of gear oil as the unsung hero of your transmission. It does far more than just lubricate. Getting the fluid level perfect is critical for the long-term health and performance of your Land Cruiser’s manual gearbox.
This is one of the most important parts of any 105 series gearbox oil capacity care guide. The right amount of oil ensures every gear, bearing, and synchronizer is coated in a protective film that prevents metal-on-metal contact, dissipates heat, and carries away microscopic wear particles.
The Dangers of Underfilling
Running your gearbox low on oil is like asking a marathon runner to compete without water. The components will quickly overheat, leading to accelerated wear on gears and bearings.
You’ll notice symptoms like whining noises, difficult shifting, and eventually, catastrophic failure. The top gears and bearings are often the first to suffer, as they rely on the oil being “splashed” up to them by the lower gears.
The Problems with Overfilling
More isn’t always better. Overfilling a gearbox can be just as damaging. Too much oil can cause the fluid to foam up as the gears churn through it, reducing its ability to lubricate effectively.
This aeration creates excess pressure inside the transmission case, which can blow out seals and gaskets, leading to messy, hard-to-fix leaks. This is a common problem with 105 series gearbox oil capacity when people guess instead of following the proper procedure.
The Definitive 105 Series Gearbox Oil Capacity Guide
So, what’s the magic number? The answer depends slightly on which specific manual transmission your 105 Series is equipped with. Toyota primarily used two very robust 5-speed manual gearboxes in these trucks: the H150F and the H151F.
Knowing the correct figures is the foundation of this 105 series gearbox oil capacity guide, but understanding the method is what guarantees success.
Identifying Your Gearbox: H150F vs. H151F
The easiest way to identify your gearbox is to check the manufacturer’s plate, usually located on the firewall in the engine bay or on the driver’s side door jamb. Look for the “TRANS/AXLE” code. An H150F or H151F code will be listed there.
Generally, the H150F was paired with the 1HZ diesel engine, while the H151F was matched with the more powerful 1HD-FTE turbodiesel and the 1FZ-FE petrol engines. They are very similar, but have slight internal differences and capacities.
Official Capacities and The “Fill-to-Spill” Method
Here are the factory-specified “dry fill” capacities. Remember, you’ll rarely get all the old oil out, so these are a starting point.
- H150F Gearbox: Approximately 2.2 Liters (2.3 US Quarts)
- H151F Gearbox: Approximately 2.7 Liters (2.9 US Quarts)
However, the most accurate and trusted method for any DIY mechanic is the “fill-to-spill” technique. This is one of the most crucial 105 series gearbox oil capacity best practices. You simply fill the gearbox through the fill hole until the oil begins to slowly seep back out. This ensures the level is exactly at the bottom of the plug opening, which is the correct fill level designated by the manufacturer.
What Type of Gear Oil to Use?
Using the correct type of oil is just as important as the quantity. For the H-series gearboxes, Toyota specifies a high-quality gear oil.
Look for a gear oil with a viscosity of SAE 75W-90. The most important specification is the API rating. You should use an oil rated API GL-4 or GL-5. There is some debate, but a quality GL-5 is generally backward-compatible and safe for the synchronizers in these gearboxes.
How to Check and Refill Your 105 Series Gearbox Oil: A Step-by-Step Walkthrough
Ready to get your hands dirty? This process is straightforward and incredibly rewarding. Following this guide on how to 105 series gearbox oil capacity will ensure a smooth, trouble-free job.
Tools and Supplies You’ll Need
- 24mm socket or wrench (for the fill and drain plugs)
- Ratchet and a short extension
- Breaker bar (just in case)
- Drain pan (at least 5-quart capacity)
- Fluid transfer pump or bottle with a flexible hose
- New drain and fill plug gaskets/washers (Part #90430-18008 or equivalent)
- About 3 quarts (or 3 liters) of 75W-90 GL-4/GL-5 gear oil
- Shop rags or paper towels
- Safety glasses and gloves
Safety First: Pre-Check Essentials
Before you crawl under your rig, ensure your safety. Park the vehicle on a perfectly level surface. This is not optional; it’s critical for getting an accurate fluid level reading.
Engage the parking brake and chock the wheels. It’s also helpful to drive the vehicle for 5-10 minutes beforehand to warm the gear oil, which helps it drain more completely.
The Step-by-Step Process
- Locate the Plugs: Slide under your truck on the driver’s side. You’ll see two large plugs on the side of the gearbox. The lower one is the drain plug, and the upper one is the fill plug.
- CRITICAL Pro-Tip: Always, always, always loosen the fill plug first! You don’t want to drain all the oil only to find out you can’t get the fill plug open to put new oil back in. Use your 24mm socket and breaker bar if needed.
- Drain the Old Oil: Once the fill plug is loose, place your drain pan underneath the drain plug. Remove the drain plug completely and let the old oil drain out. Be prepared for it to come out quickly at first.
- Inspect the Drain Plug: The drain plug is magnetic. It’s normal to find a small amount of fine, metallic paste on it. However, if you see large metal chunks or slivers, it’s a sign of internal damage that needs professional inspection.
- Replace the Drain Plug: Clean the drain plug thoroughly. Install a new washer and tighten the plug snugly. The torque spec is around 29 ft-lbs (39 Nm), but “good and tight” with a standard ratchet is usually sufficient. Don’t overtighten it.
- Fill with New Oil: Insert the hose from your fluid pump or bottle into the fill hole. Slowly pump the new 75W-90 gear oil into the gearbox. Keep going until you have a slow, steady trickle of oil coming back out of the hole.
- Check the Level and Replace Plug: Once it starts to trickle out, the level is perfect. Let it stop dripping, clean the fill plug, install its new washer, and tighten it to the same spec as the drain plug.
- Clean Up and Test Drive: Wipe down the gearbox to check for any leaks later. Properly dispose of your used oil. Take the truck for a short drive and enjoy your noticeably smoother shifts!
Common Problems and Pro Tips for Your Gearbox Oil Change
Even a simple job can have its quirks. Here are some pro-level 105 series gearbox oil capacity tips to help you handle common issues that might pop up.
The Dreaded Stuck Fill Plug
If your fill plug won’t budge, don’t panic. A good six-point 24mm socket and a long breaker bar are your best friends. You can also try a few sharp taps with a hammer on the head of the ratchet to shock the threads loose. A little bit of penetrating oil applied beforehand can also work wonders.
Interpreting Metal Shavings on the Drain Plug
A fine, grey, metallic sludge on the magnet is normal wear and tear. It’s what the magnet is there to catch. However, if you find anything that looks like a piece of a gear tooth, a needle from a bearing, or shiny brass/bronze-colored flakes (from synchros), it’s time to consult a transmission specialist.
How Often Should You Change Your Gearbox Oil?
For a 105 Series Land Cruiser, especially one that sees off-road use or towing, a good interval is every 30,000 to 40,000 miles (50,000 to 65,000 km). If you do frequent water crossings, you should check your oil for milky contamination afterward and change it immediately if any is found.
Eco-Friendly and Sustainable Gearbox Oil Practices
Being a responsible DIYer means taking care of the environment too. Following eco-friendly 105 series gearbox oil capacity practices is simple and important.
Proper Disposal of Old Gear Oil
Used gear oil is a hazardous material. Never pour it down the drain, on the ground, or in the trash. Collect it in a sealed container (like the empty oil bottles) and take it to your local auto parts store or a municipal recycling center. Most places accept it for free.
Minimizing Waste
One of the benefits of knowing the exact 105 series gearbox oil capacity is buying only what you need. Purchasing three 1-quart or 1-liter bottles is usually perfect for the job, minimizing leftover, half-used containers sitting in your garage.
Frequently Asked Questions About 105 Series Gearbox Oil Capacity
What are the symptoms of low gearbox oil in a 105 Series?
The most common signs are difficulty shifting (especially when cold), a “notchy” or grinding feeling when changing gears, and whining noises from the transmission that change with engine speed.
Can I use a different weight of gear oil, like 80W-90?
While 80W-90 might work in a pinch in very warm climates, the specified 75W-90 provides better cold-weather performance and protection over a wider temperature range. It’s best to stick with the manufacturer’s recommendation for optimal performance.
Is it okay to mix different brands of gear oil?
It’s not ideal, but it’s better than running low on oil. If you are just topping off, using a different brand of the same specification (e.g., 75W-90 GL-5) is acceptable. For a full drain and refill, it’s best practice to use a single brand.
How much does it cost to have a shop change the gearbox oil?
Depending on labor rates and the cost of oil, you can expect a professional shop to charge anywhere from $100 to $200 for this service. By doing it yourself, you can save a significant amount and gain valuable experience with your vehicle.
Mastering the 105 series gearbox oil capacity and refill procedure is a fundamental skill for any Land Cruiser owner. It’s a job that directly impacts your vehicle’s health and your driving experience. By following this guide, you’ve not only saved money but have also ensured that one of the most vital components of your legendary 4×4 is protected for the adventures ahead.
Stay safe, keep wrenching, and enjoy those smooth shifts!
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