It may seem strange that as someone who is called out to fix washing machines, I often have to explain to disbelieving owners that there is nothing wrong with their machine. Usually these soul-weary guardians of the household linen will point to a machine caked up with thick layer of muddy grime, and point to oily stains on their blacks and whites that have them convinced their machine gearbox has sprung a leak.
On these jobs, although my toolbag stays in the car, what takes the longest time is convincing the owner that there is nowhere in the machine that has engine oil or gearbox oil. Once that is done, it takes almost as long to explain to them how to cure the problem.
The problem is being caused as a result of the removal of phosphates from all of todays detergents. Phosphates were an ingredient of all detergents until 2011, when they were removed because of the catastophic harm they causing in rivers and lakes. The job of the phosphates was to keep the dirt in suspension in the water until it left the machine. Without the phosphates, this dirt is now settling onto the machine parts. The cure for this increasingly common issue is just to clean the machine regularly. Newer machines have a Tub-Clean function that is intended to combat exactly this issue. If your machine doesn't have this function, a less-effective approach is run the machine without clothes on the Cotton cycle at 60 degrees on a regular basis.