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Why is My Transmission Shifting Hard?

Outdoors May 16, 2018 Sonia



Automatic transmissions are a mystery to most. Many mechanics will quickly tackle a timing belt job or a head gasket replacement, but when it comes to transmission problems even the most seasoned mechanics often shy away. When they work correctly, we usually don’t think about them because they are automatic. When they don’t work correctly, it usually goes past annoying and leaves you stranded.

Automatic transmissions use a planetary gear system to transfer power and to create different gear ratios and a reverse option. A planetary gear set has a single center gear, a large ring gear around that with internal teeth, and multiple small gears in between the center and ring gears. In an automobile transmission, there usually are two sets of these gear systems. This arrangement allows for a variety of gear ratios that can be shifted very easily, but if one part of the system fails, it often renders the whole system inoperable.

Like many problems that arise in your car, there are usually early warning signs to let you know that one of these systems is about to fail. Luckily the automatic transmission in your vehicle has some early warning signs of its own.

Automatic Transmission Failure Early Warning Signs:

  • Low fluid level on the dipstick
  • Dark or discolored fluid
  • Whining or grinding noises
  • Loose shifting or over-revving
  • Hard or jerky shifting

The best way you can keep tabs on your transmission and make sure it lasts as long as possible is to make sure it always has enough clean transmission fluid. Most passenger vehicles today have a dip stick in the engine bay for the automatic transmission. Check your manual for the location of the dip stick and the recommended procedure for checking the level. On most vehicles the transmission level should be checked with the engine operating, and there will be a “cold” and “hot” range. It is easiest to check the fluid level in the morning after your car has sat all night and is cold. In this case use the “cold” range. If you’ve been driving and want to check your fluid level, try operating your vehicle in the lower gear to ensure the transmission fluid is sufficiently hot and use the “hot” range on the dip stick.

While checking the fluid level, check the fluid for discoloration, particles or a burnt smell. If any of these are evident, it may be time to change your transmission fluid. You should always change your transmission fluid at the factory recommended interval using the recommended fluid for your vehicle. If you use your vehicle for towing, driving in the city or in stop-and-go traffic, or you live in a significantly warm or cold place, you may need to change your fluid 10 to 25 percent more often.

Another way to diagnose an impending transmission problem is if it starts making whining or grinding noises. This would signal a major problem, and the vehicle should be taken to a dealer or transmission repair shop immediately.

How the transmission shifts compared to normal is another way you can tell if something is going wrong in your automatic transmission. An automatic transmission shifts gears by changing which of the planetary gears are moving, held stationary or coupled to the input or output shafts. These changes are made by a series of clutches and bands and are activated by pressure changes of the transmission fluid. As these clutches and bands wear out, it can cause your shifts to feel sloppy, take longer or even have the engine over-rev. The wear of these clutches and bands is accelerated by having dirty transmission fluid circulating, causing excessive wear and premature failure. In this case, a transmission rebuild is the only thing that can solve the problem.

If you are experiencing hard transmission shifts, it is possible that the only problem is a low transmission fluid level. Low transmission fluid can change the operating pressures of the transmission, as well as reduce the amount of lubricant present between the clutches and bands, and raise transmission temperatures. All these things can cause hard or jerky shifting. You need to identify why the transmission has a low fluid level and refill it as soon as possible.

If your transmission has a low fluid level, it is likely due to a leak in the transmission. Leaks are most commonly found in input or output shafts on the transmission, because this is where the moving parts exit the case. There will be a rubber seal around each shaft that can wear, shrink or get brittle over time. These seals can often be difficult and expensive to replace because of their location on the vehicle.

Rather than replacing them, add BlueDevil Transmission Sealer to your automatic transmission fluid. BlueDevil Transmission Sealer is specially formulated to restore dried, cracked or shrunken seals and gaskets in your transmission without harming the transmission. BlueDevil Transmission Sealer is guaranteed to form a permanent seal. BlueDevil products are safe for your vehicle and can remain in the system until your next fluid change.

Look for the early warning signs of transmission problems to save yourself money and a headache down the road.

Editor’s Note: This article is sponsored by BlueDevil Products®, manufacturers of quality sealants for the automotive aftermarket industry, supplying over 400 distribution centers across North America, South America, Europe, Asia and South Africa. For more information on BlueDevil Products, visit www.gobdp.com.

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