When it comes to preventive maintenance on our vehicles, most of us remember to get our oil changed. But services that occur at longer intervals—like transmission service—sometimes get overlooked. Yet transmission service is a critical part of car care. A poorly maintained transmission will reduce fuel economy and lead to expensive repairs. The transmission transfers power from the engine to the drive wheels. When it’s clean and well-lubricated, it gives maximum fuel efficiency. But when it gets dirty or worn down, your fuel economy will suffer. Your transmission relies on transmission fluid to keep everything running well.
Transmission fluid has two jobs: to cool and lubricate the transmission. The transmission operates at high temperatures. It can get 100-150°F degrees hotter inside your transmission than inside your engine. Transmission fluid transfers some of the heat away from the transmission. Transmissions work hard. Their parts need constant lubrication to prevent excessive wear and keep them running smoothly.The constant shifting and movement of gears inside the transmission cause bits of the gears and clutch material to wear off. These bits of grit get into the transmission fluid. This grit increases friction inside the transmission and causes even more wear – it’s like liquid sandpaper. Also, the high temperatures inside the transmission cause the transmission fluid to break down over time, making it a less effective lubricant. The fluid can actually become sludgy, which can gradually plug up the maze of passages inside the transmission. Gradually, the transmission loses efficiency and stops operating smoothly. Eventually, the transmission will be damaged or fail altogether.
This is why the transmission fluid must be changed periodically. Your owner’s manual will give you a recommended time schedule for this service. Or, you can ask at your service center. Generally, the interval is around 35,000 miles (55,000 km) or every two years. But the interval for your vehicle may be shorter or longer.
Of course, if you give your transmission a real workout, you’re going to have to change the fluid more often than the manufacturer recommends. If you drive in hot, dusty conditions, if you tow a trailer, if you haul heavy loads or if you do a lot of stop-and-go driving, then you need to change your transmission fluid more often. Also, if you demand frequent bursts of speed from your engine—especially shooting away from stops—your transmission is working harder and will need more frequent care. Check your owner’s manual for the “severe conditions” service interval.
Transmission fluids vary from vehicle to vehicle, so you’ll also need to check your owner’s manual to know what kind your vehicle needs, ask your service advisor. Transmission fluid can usually be changed while you wait and is not particularly expensive. Compared to the cost of transmission repairs or a new transmission, it’s downright cheap! So take some good auto advice and take care of your transmission. It will pay you back in improved fuel efficiency and a longer, smoother ride.