28/11/2025
For owners of the iconic 2007 BMW GS, the question of final drive maintenance often arises, particularly concerning the process of changing the gear oil. While many modern vehicles offer a simple drain plug for fluid changes, the BMW GS final drive unit presents a slightly more involved procedure. This comprehensive guide will walk you through the specifics, ensuring your beloved GS continues to perform flawlessly on the open road, whether you're tackling motorways or venturing off the beaten track.
The direct answer to whether a 2007 BMW GS final drive has a drain plug is yes, it does. However, unlike a simple oil pan drain, the design of the BMW GS final drive unit necessitates its removal from the motorcycle for proper servicing. This isn't merely to access the drain plug; it's a crucial step that allows for vital inspections and lubrication that cannot be performed with the unit still mounted. Attempting to simply suction fluid out is not feasible due to the unit's tight internal design, which prevents any hose from fitting adequately.
Why Dropping the Final Drive is Essential
The process of removing the final drive unit goes beyond just draining and refilling gear oil; it's an opportunity for preventative maintenance that can save you significant expense and headaches down the line. When the final drive is off the bike, you gain access to critical components that are otherwise hidden. This includes:
- Inspecting the U-Joints: These universal joints are vital for transmitting power smoothly from the gearbox to the final drive. Regular inspection allows you to check for any signs of wear, play, or corrosion. Catching issues early can prevent catastrophic failure and ensure a safe ride.
- Lubricating the Drive Splines: The splines, which connect the driveshaft to the final drive, require proper lubrication to prevent wear and corrosion. Over time, grease can dry out or become contaminated. This is a prime opportunity to clean and re-grease them, ensuring smooth power transfer and preventing binding. Honda Moly 60 is widely regarded as the best choice for this task due to its high molybdenum content, though most any good quality moly grease will offer adequate protection.
- Checking for Rust: Moisture ingress can lead to rust formation within the final drive housing and on critical components. With the unit removed, you can thoroughly inspect for any signs of rust, which if left unchecked, can compromise the integrity and lifespan of the final drive.
These inspections are not optional; they are fundamental to the longevity and reliability of your BMW GS's drivetrain. Neglecting them can lead to premature wear of expensive components.
Tools and Materials You'll Need
Before you begin, gather all the necessary tools and materials to ensure a smooth and efficient final drive service:
- Good quality synthetic 75W-90 GL5 rated gear oil (e.g., Mobil-1, Valvoline Syn)
- Honda Moly 60 grease or equivalent high-quality moly grease
- Staburags NBU 30 PTM grease or a suitable substitute (sticky grease safe for plastic/rubber with good water resistance)
- New O-rings for the speed sensor and the drain plug (these are inexpensive and vital for preventing leaks)
- Plastic squeeze bottle (from hairdressing supply stores) or a 100ml plastic syringe (medical or industrial supply stores/online)
- Basic hand tools (spanners, sockets, torque wrench for reassembly)
- Clean rags or shop towels
- Drain pan for old fluid
- Brake cleaner or a similar degreaser for cleaning components
Step-by-Step Final Drive Service Guide
While specific removal and reinstallation steps for the final drive unit itself are beyond the scope of this general article (as they can vary slightly by model year and require specific torque settings), the following outlines the fluid change and inspection procedure once the unit is off the bike.
Preparation and Removal
Ensure your motorcycle is securely on its centre stand or a suitable lift. Safely remove the final drive unit from the swingarm. This usually involves disconnecting the rear wheel, braking components, and the driveshaft. Consult your motorcycle's service manual for exact removal instructions and torque specifications for reassembly.
Draining the Old Fluid
With the final drive unit removed and placed over a drain pan, locate the drain plug. Remove the drain plug and allow all the old gear oil to drain completely. It's often beneficial to let it drain for a while to ensure maximum fluid removal. Once drained, clean around the drain plug opening.
Speed Sensor Removal and Cleaning
Carefully remove the speed sensor. This is a delicate component, so handle it with care. Once removed, thoroughly wipe the speed sensor clean. Pay attention to any build-up or debris. This is also the point to remove and discard the old O-ring from the speed sensor.
Inspecting U-Joints and Splines
Now that the final drive is disconnected from the driveshaft, inspect the driveshaft's U-joints for any play, stiffness, or signs of corrosion. Next, thoroughly inspect the drive splines on both the driveshaft and the final drive input shaft. Look for wear, pitting, or rust. Clean any old grease and debris from the splines.
Lubricating the Splines
Apply a generous, even coat of Honda Moly 60 grease (or your chosen moly grease) to the drive splines on both the driveshaft and the final drive input shaft. This lubrication is vital for preventing wear and corrosion, ensuring smooth engagement and power transfer.
Replacing O-Rings
Before reassembly, it is absolutely essential to replace both the speed sensor O-ring and the O-ring on the drain plug. These O-rings are inexpensive but critical for maintaining a proper seal and preventing leaks from this expensive drive unit. Lubricate the new O-rings lightly with some fresh gear oil before installation.
Refilling the Final Drive
The specified refill amount for the 2007 BMW GS final drive is 180ml of good quality synthetic 75W-90 GL5 rated gear oil. This is a precise measurement, so accuracy is key. You can use a plastic squeeze bottle, commonly found at hairdressing supply stores, or a large plastic syringe. Many owners find a 100ml syringe, filled to 90ml and used twice, to be very effective. Simply stick the tip of the syringe or squeeze bottle into the refill port and slowly push the plunger or squeeze the bottle until the correct amount is dispensed. There is no need for a section of hose with the syringe method.
Reassembly and Sealing
Once refilled, replace the drain plug with its new O-ring and tighten it to the manufacturer's specified torque. Reinstall the speed sensor with its new O-ring. Now, carefully reattach the final drive unit to the motorcycle. Ensure that the plastic clips and rubber boot are correctly seated. It is highly recommended to apply Staburags NBU 30 PTM grease at both ends of the rubber boot. This specialised grease helps to create a robust seal, protecting the unit from moisture ingress. If Staburags is hard to find, any sticky grease that is safe for plastic/rubber components and offers good water resistance can be used as a substitute; many owners successfully use moly grease for this purpose as well.
Final Checks
Once everything is reassembled, double-check all fasteners for correct torque. Wipe down the final drive unit to remove any oil residue. Conduct a visual inspection for any signs of leaks after a short ride. This detailed attention ensures your final drive is properly sealed and ready for many more miles.
Gear Oil Recommendations
When it comes to gear oil, opting for a good quality synthetic 75W-90 GL5 rated oil is paramount. You don't necessarily need to purchase the expensive, dealership-branded fluid. Reputable brands offer excellent alternatives at a fraction of the cost.
Feature Mobil-1 / Valvoline Syn 75W-90 GL5 Dealership Branded 75W-90 GL5 Quality Excellent, high-performance synthetic Excellent, high-performance synthetic Cost Relatively inexpensive, good value Significantly more expensive Availability Easily found at local auto parts stores Typically only available at BMW dealerships Performance Meets or exceeds manufacturer specifications Meets or exceeds manufacturer specifications Grease Choices for Splines and Boots
The choice of grease is equally important for the longevity of your final drive components.
Application Primary Recommendation Acceptable Substitutes Notes Drive Splines Honda Moly 60 Any high-quality moly grease (e.g., Castrol, Lucas) High molybdenum content for extreme pressure lubrication. Critical for preventing spline wear. Rubber Boot Ends Staburags NBU 30 PTM Any sticky grease safe for plastic/rubber with good water resistance (e.g., moly grease, marine grease) Provides an excellent moisture seal. Staburags is difficult to source, so alternatives are commonly used. Common Pitfalls to Avoid
- Ignoring O-Rings: Failing to replace the speed sensor and drain plug O-rings is a common mistake that almost guarantees a leak. They are cheap; replace them!
- Incorrect Fluid Volume: Overfilling or underfilling the final drive can lead to premature wear or overheating. Stick precisely to the 180ml specification.
- Skipping Inspections: The primary reason for dropping the final drive is to inspect the U-joints and splines. Do not skip these vital checks.
- Improper Seating of Boot/Clips: If the rubber boot and its plastic clips are not correctly seated and sealed, moisture and contaminants can enter the unit, leading to rust and damage.
Benefits of Regular Final Drive Maintenance
Adhering to a regular final drive service schedule offers numerous benefits:
- Extended Component Lifespan: Proper lubrication and clean fluid significantly reduce wear on gears, bearings, and splines.
- Smoother Operation: Well-lubricated splines and fresh gear oil contribute to a smoother, quieter, and more efficient power delivery.
- Early Detection of Issues: The inspection process allows you to identify minor issues (like slight play in U-joints or early signs of rust) before they escalate into costly failures.
- Enhanced Safety: A well-maintained final drive is less likely to fail unexpectedly, contributing to a safer riding experience.
- Preservation of Resale Value: A motorcycle with a documented history of proper maintenance will always command a higher resale value.
Frequently Asked Questions (FAQs)
How often should I change the final drive fluid on my 2007 BMW GS?
BMW typically recommends final drive fluid changes at specific service intervals, often every 20,000 to 40,000 kilometres, or every two years, whichever comes first. However, many experienced riders and mechanics advocate for more frequent changes, especially if you ride in harsh conditions (e.g., heavy rain, dusty roads, extreme temperatures) or engage in spirited riding. Some opt for an annual fluid change as cheap insurance for this critical component.
Can I just suction out the old fluid instead of dropping the final drive?
No, unfortunately, you cannot effectively suction fluid out of the 2007 BMW GS final drive. The internal design of the unit is too tight and complex to allow a hose to reach the lowest points and extract all the old fluid and any accumulated sludge. More importantly, suctioning would bypass the essential inspections and lubrication of the U-joints and drive splines, which are the primary reasons for removing the unit in the first place.
What happens if I don't change the final drive fluid or perform maintenance?
Neglecting final drive maintenance can lead to several serious issues. Over time, gear oil degrades, losing its lubricating properties. This can cause increased friction, heat, and wear on the internal gears and bearings. Lack of spline lubrication can lead to wear, binding, and eventual failure of the driveshaft connection. Ultimately, this can result in catastrophic final drive failure, leaving you stranded and facing extremely expensive repair or replacement costs.
What are the signs of final drive issues?
Common signs of a failing or problematic final drive include unusual noises (whining, grinding, clunking, especially when accelerating or decelerating), excessive play in the rear wheel when the bike is on its centre stand (check for side-to-side or up-and-down movement), fluid leaks around the unit, or a burning smell. If you notice any of these symptoms, it's crucial to address them immediately.
Is this a DIY job, or should I take my BMW GS to a professional mechanic?
While this guide provides a detailed overview, the final drive service on a 2007 BMW GS is considered an intermediate to advanced DIY task. It requires specific tools, mechanical aptitude, and adherence to torque specifications. If you're uncomfortable with motorcycle mechanics, lack the necessary tools (especially a torque wrench), or are unsure about any step, it is highly recommended to take your bike to a reputable professional BMW mechanic. The cost of a professional service is far less than the cost of repairing damage caused by incorrect procedures.
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