The most forgotten maintenance procedure is the replacement of the Toyota transmission filter on your vehicle. Unlike the oil pan, the transmission pan does not have a plug in it to make this changing of the oil a simple process. The recommended timing of the transmission filter to be replaced along with the automatic transmission fluid is at or near the 35,000 mile mark. This periodic maintenance procedure generally goes undone because most Toyota owners feel their automatic transmission is operating normally. The danger of not replacing the Toyota transmission filer and fluid is that this filter does not have a check valve in it like the oil filter, and if it does become obstructed with contaminates the flow of the automatic transmission fluid will be reduced; causing excessive wear on the transmission. It will also cause it to malfunction and begin to slip instead of remaining in gear. The replacing of the transmission filter involves the removal of the transmission pan with the fluid still inside of it. This is messy no matter how it is done. Once the pan and fluid is removed, access to the transmission filter can be accomplished. In the bottom of the pan is also a magnet that should be cleaned of any metal shavings that it collects. Small pieces the size of sand metal is normal. If larger pieces are noticed, then the transmission has a more severe problem than just the fluid in need of being replaced on your Toyota. If the transmission filter and fluid is not regularly replaced, the wear on the transmission will be excessive. Before the Toyota reaches 100,000 miles, the transmission will more than likely have to be rebuilt ort replaced because it is malfunctioning.