| Powertrain By Pete Kaftantzis, ASE Master Certified Technician, SKF Why proactive u-joint maintenance? It protects fl eets and drivers Most rear-wheel drive trucks and four-wheel drive trucks integrate u-joints as part of the driveshaft assembly. Th ese components handle the misalignment between the transmission and the rear axle, while transferring power to move the vehicle. Proactive u-joint maintenance, repair and replacement are critical for improving the performance and safety of your fl eet. Taking a reactive approach and waiting until u-joints break and fail completely can lead to the all-too-familiar scene of the immobile truck by the side of the road with the unattached driveshaft lying on the ground beneath the vehicle. Th is scenario is both dangerous and costly. Here are some recommendations proactive measures to share with your technicians. Heed Warning Signs Before taking the time to remove the u-joint to inspect for damage, there are telltale signs of u-joint problems you should pay attention to. One of the earliest signs of u-joint damage is squeaking. It’s generally caused by metal-onmetal contact due to insuffi cient grease. You’ll likely only hear this sound when starting to move, as it will be drowned out by other noises once the vehicle is moving any faster than 5 mph. Another common sign of u-joint problems is hearing a “clunk” with a ringing sound when moving the shift er between “Drive” and “Reverse.” Th is sound may be an indication of excessive clearance in the u-joints. A third, and more serious symptom of u-joint damage is vehicle vibration when moving at higher speeds. Th is occurs when u-joint bearing wear has become severe enough to allow the driveshaft to move outside its normal rotational path. Part of the reason this symptom is more serious is that it means the u-joint is now so worn that it may be causing damage to the transmission as well. It’s important to be able to distinguish between vibration due to u-joint wear and vibration due to wheel imbalance. Vibration due to u-joint wear is typically a higher frequency since the driveshaft turns much faster than the wheels. Also, wheel balance issues create a steady vibration, while vibration from a worn u-joint is felt during acceleration or deceleration. With proactive u-joint maintenance, repair and replacement, fl eets can avoid having a u-joint break and fail completely, leading to an immobile truck by the side of the road with the unattached driveshaft lying on the ground beneath the vehicle. Photo courtesy of SKF Inspection Time Now that you suspect developing u-joint problems, it’s time to inspect the component. You’ll need to start by removing the driveshaft from the truck. Before removing the driveshaft , it is imperative to draw alignment marks on the driveshaft fl ange and the diff erential pinion fl ange. You’ll need to align these marks when you reinstall the driveshaft to make sure you’re spinning the driveshaft in the same position. Once you have the driveshaft removed, inspect the u-joint. Hold the driveshaft in one hand and the fl ange yoke in the other. Spin the fl ange yoke lock to lock in both directions. If you feel any type of binding or looseness, the u-joint needs to be replaced. Removal Start by removing the four retaining clips that hold the u-joint in place. Once the retaining clips have been removed, SKF recommends using a ball- CK-4 and FA-4 are here By Brian Humphrey, OEM Technical Liaison, Petro-Canada Lubricants On December 1, the North American lubricants industry witnessed its biggest specifi cation overhaul in history with the launch of the new American Petroleum Institute (API) heavy duty diesel engine oils CK-4 and FA-4. After years in development, these new oils mark a signifi - cant step-change for the industry as it meets the Phase 2 Greenhouse Gas Emissions requirements to reduce carbon emissions and fuel consumption. OEMs are also responding to this legislation by developing smaller, more effi cient engines that can run on lower viscosity oils which, in turn, can deliver improved fuel economy. BASIC DIFFERENCES API CK-4 will offer backwards compatibility to the previous categories (CJ-4, CI-4, etc.), allowing use in the vast majority of older diesel engine vehicles while offering increased performance and protection gains, as well as the ability to extend the intervals required between oil changes. API FA-4 is specifi cally designed for newer vehicles. These oils will have a lower viscosity, meaning less friction in the engine and a reduction in fuel consumption, while still offering increased levels of wear protection. Future heavy duty fl eet vehicles will be designed to comply with this specifi cation to offer even higher levels of effi ciency. The crucial point to be aware of is FA-4 oils have limited backwards compatibility, as they are specifi cally intended for newer engines designed to meet the new legislation around emissions and fuel economy. As many older engines are not designed to operate with such lower viscosity oils, using FA-4 oils in these engines could damage hardware if used for an extended period of time. The new oil classifi cations will not affect every business the same and some fl eets may only see a small impact. Therefore, the decision about which oil is most suitable is dependent on the age of the truck and the ability of the engine to run lower viscosity oils. For example, a fl eet which operates with older equipment and different engine types may simply need to transition from the current CJ-4 oils to CK-4 oils. For those fl eets with a mix of older and newer equipment, and an ambition to realize the improvements that will come with the new classifi cation, a stock of both CK-4 and FA-4 products may be best. We strongly advise fl eets to consult their engine/vehicle OEM manuals to ensure that they are using the correct oil for their vehicle. API has released new Service Symbols, known as donuts, which clearly distinguish between the two oil subcategories. We recommend visiting www.api.org to get familiar with the different symbols. EXPECTATIONS Our expectation is that the majority of OEMs will recommend and/or allow CK-4 oils as the next step up from CJ-4 due to their backwards compatibility. As the FA-4 oils have specifi cally been designed for 2017 on-highway engines, we expect to see adoption of this category build from January onwards as OEMs release their recommendations. We anticipate the integration of API FA-4 oils in fl eets’ stock will then increase exponentially each year as fl eets see the potential cost benefi ts they can achieve, and OEMs design improved engines – often downsized and operating at higher temperatures – to meet legislation standards. Brian Humphrey is OEM technical liaison for Petro-Canada (lubricants.petrocanada. ca). It blends and packages more lubricants, specialty fluids and greases. 40 FLEET MAINTENANCE ❚ NOVEMBER/DECEMBER 2016 ❚ VehicleServicePros.com
FleetMaintenance_NovemberDecember_2016
To see the actual publication please follow the link above