The forgettables

Field maintenance is important, but have you recently checked these easily missed parts that every vehicle relies on?

Most all of us are aware of the need for vehicles to be maintained through various services. Some of the activities such as oil and filters changes are still common, but even grease jobs on many cars and light duty vehicles have been eliminated. There are, however, some items that I notice that are commonly ignored and this neglect can lead to some major expenses later on. They all have lubricants and fluids that should be serviced periodically according to a factory maintenance schedule. With all five items, be sure to use the proper fluid per the manufacturer when servicing, as there used to be few “choices” and now there are many.

  • Rear Differential – if unit is posi or limited slip you may have to add an additive for the clutch packs to work correctly.
  • Coolant – Gone is the day of one green fluid fits all. Many types of coolants now exist, depending on manufacturer, and the correct fluid is critical to avoid problems later on. Keep in mind ethylene glycol never loses its ability to not freeze, unless diluted. However, contamination and loss of additives within coolant could lead to corrosion in the cooling system with drastic results. I strongly advise any reader with a 7.3 Ford diesel and early 6.0 diesels to reference your owner’s manual as they have recommended service at 15,000-mile intervals.
  • Manual Transmission – Consider servicing this more often than scheduled as operator ability (or inability) may affect what is “floating around” in the gear oil, especially if operated by multiple drivers. Some truck transmissions may have large capacities and use synthetic gear oil, making oil replacement expensive. A trick we do is to replace the magnetic drain plug (with another on hand) annually allowing only minimal loss of oil, with removal of metallic particles to avoid contamination.
  • Front Differential and Transfer Case – These two are truly the Rodney Dangerfields of auto repair, as they are rarely maintained and get no respect. The front differential should get serviced at the same time as the rear differential; however, no additive is normally needed as they are rarely posi. As far as the transfer case is concerned, again, many different fluids are used. I suggest factory fluid to avoid misapplication and cross contamination.

Even more important than following the service schedule, which may be at 80,000 or more, is to physically check the oil level at least once a year. Keep in mind a small leak over time will allow the items to run “dry” causing catastrophic expensive failures which I have seen many times. We at Krehel Auto check these levels once a year as part of our winterization service and suggest you do the same. By the way, if your fleet is being “maintained” by “in house” personnel and their greatest attribute is that they are paid very little (be honest with yourself) an annual check-over by a reputable shop is strongly recommended.

Automatic transmissions also have a maintenance schedule and many shops perform maintenance. However, if the vehicle is used for plowing, servicing may be required more often, especially after a long winter’s usage.

Keith Krehel, president of Krehel Automotive Repair, Inc., in Clifton, N.J., is a 30-year veteran of the snow industry and has been repairing, modifying and occasionally resurrecting snow plow equipment even longer. He can be reached at