The Fountain of Youth: Oil and Grease
To loosen the single oil filter on this C15, Weitzel had to work from below with a strap wrench, socket and extension.
The battle to stay young is never ending. For people, there are vitamins, supplements and all sorts of goop you can put onto your skin. But when it comes to your truck, lubrication is what keeps it young.
Done properly and regularly, lubing will reduce maintenance costs and even enhance safety.
We consulted Mark Grunenwald, profit center manager, and technician Dale Weitzel, of the Travel Centers of America truckstop in Paulsboro, N.J., for advice on the proper procedure for lubrication.
Changing the oil
After the engine is hot, turn off the ignition switch and remove the keys. Make sure to mark the switch or tell everyone around that the engine must not be started until the oil is replenished.
- Place a drain pan under the drain plug. Use the right size box or Allen wrench and remove the drain plug, catching it in your fingers. You may want to wear gloves, as the oil and plug will be hot.
- Wipe the plug clean and inspect it. Replace any cracked or damaged seal rings. Replace the entire plug if threads or the wrenching flats on the head are damaged.
- Make sure the drain pan is underneath the engine oil filter or filters as well. If there are two filters or three that are different from one another, note where the full flow and bypass filters are mounted. Then, using a strap wrench of appropriate size, turn the filter counterclockwise as viewed from underneath and remove it.
- Wipe the filter mounting(s) thoroughly with a clean rag. Make sure the filter-sealing ring has come off the mounting. If not, remove it.
- Read the directions on the side of each filter to determine how far to turn it for proper sealing. Usually, this will be 3/4 to 11/4 turn past the point where the gasket touches the mounting.
- Make sure to use an engine oil that meets the standards required for the model and year of the engine, as detailed in the owner’s manual. Use 15W-40 oil unless running in extreme cold – check the owner’s manual for the right viscosity to use in abnormal weather.
- For proper seal, lubricate the top surface of each filter’s rubber seal thoroughly with clean engine oil. Weitzel recommends that you fill each of the filters with the oil you are putting into the system to protect the oil pump and other engine parts during the first 15-30 seconds of engine operation. Prop the filters where they will stand up, and refill them after the level has settled.
- Carefully hold each filter vertically and turn gently to start the treads onto the
fitting. If the threads catch but the filter quickly gets hard to turn, it is cross-threaded. Turn it back off right away and start again, making sure to hold the filter straight up. Once the threads catch and the filter turns easily, tighten it till it touches the mounting base. Then manually, possibly with the strap wrench, watch it as it turns and rotate it the number of turns required for proper sealing. Avoid excessive tightening.
- Once the oil stops draining from the pan, wipe the plug threads clean and reinstall the plug. Look up the torque required for the plug in the owner’s manual, and then use a torque wrench to final torque the plug until it is just right.
- Wipe the area around the oil filler plug and remove it. Refill the pan with the rated amount of oil (normally 38-53 quarts), replace the filler plug and start the engine. Idle it until oil pressure has been up for 30 seconds or so and then check for leaks. Stop the engine, allow oil to drain back into the pan for five minutes and then check the oil level, adding if necessary. Dispose of used oil and filters properly.
Checking the transmission and axle lubes
Make sure you have the right lube to add to transmission and axles – they are different. You need to add the same type you are using.
- The component makers recommend that you have the truck at operating temperature before lubing so that when checking fluid levels, the level will be normal. Carefully remove the level check plug, located about six inches up on the side of the transmission, or the same distance up on the back of the axle housing. Be careful not to remove the drain plug located on the bottom of each component.
- Check the transmission lube first. Put a drain pan under the plug. Wipe the plug and the area around it clean. Then, with the right solid (not adjustable) wrench, remove it. The fluid should be right at the level of the plug. If the lube runs out of the hole, the level is fine. If it doesn’t run out when you remove the plug, reach in to feel the level with a finger. Make sure it’s right up at the bottom of the hole, and, if not, use a small syringe to add the correct, single-weight transmission lube until it is. If the lube level was well below the hole, inspect the case and the front and rear for seal leaks. Have leaks corrected by a driveline repair shop or dealer.
- Inspect the plug and make sure the threads and seals are in good condition (no cracks or obvious wear on the seal). Replace bad parts. Then reinstall the plug, tightening until snug or torquing it to the torque specified in the owner’s manual.
- Check each of the two axle lube levels in exactly the same way, pulling the plugs from the housing rears to do so. Make sure to add only EP (extreme pressure) axle lube. Multi-weight lubes are better, especially for extreme cold. As with the transmission, inspect the plug and seal and replace parts if necessary. If the level is low, inspect for leaks and have anything obvious repaired.
The first step when greasing is to determine just what grease the manufacturer recommends for your chassis, normally an NGLI No. 2 with some EP properties. Check to see if a different grease is required for your slack adjusters. Also, some trucks with an extended maintenance interval option may be set up to use synthetic grease on certain components. Jim Grant of Trebar, Inc., 2005 Kenworth Service Council chairman, says these fittings often have special grease points, making them easy to distinguish.
Grease should be kept in a closed container. The best thing for one truck is to buy just a cartridge or two at a time to refill your grease gun.
Next, refer to a grease point diagram in the owner’s manual, or in maintenance information available at your dealer or on the Internet, so you can check the diagram as you go and make sure not to miss anything. If your owner’s manual doesn’t have a diagram, cover these categories of fittings:
- Steering universals, drag link and slip yoke. All steering joints from the steering gear itself through the control arms, tie rod (both ends), knuckle pins and kingpins.