Ask the Mechanic
WHAT IS WRONG WITH CVT GEARBOXES?
Hello Paul, I have recently acquired a Nissan which drives well. However, my mechanic says I should trade it for another car since it has a CVT gearbox which is bound to fail soon. What is wrong with CVT gearboxes?
Kiyingi
Hello Kiyingi, Do not get rid of your car since Continuously Variable Transmissions (CVT) are here to stay. Its innovators argue that CVT transmissions are better because they are easier to maintain.
CVT transmissions have less moving components, which generates less heat or wear and tear. They also provide more useable power, better fuel economy and a smoother driving experience than a traditional automatic transmission. The gears in this transmission are shifted in a manner that matches the appropriate ratio for a particular driving situation. Other car manufacturers such as Toyota, Honda, Renault, BMW, Mercedes, Jeep, Audi and VW have also built cars with CVT gearboxes which are popular.
Whereas there are no major faults with the CVT gearboxes to warrant abandoning them, there are a couple of avoidable user and maintenance challenges experienced with this gearbox technology. The most common challenge is user apathy. A number of motorists do not even know whether they have a CVT gearbox and when their driving experience is odd, they think the gearbox is defective as it shifts continuously rather than in steps.
Step one for managing a CVT gearbox is to tell whether your car has one by reading the user manual or checking the dipstick which will have CVT inscribed on it. Also, read about the seamless shifting pattern of a CVT gearbox to understand how it works.
Another challenge is maintenance. CVT transmissions use special CVT oil. A number of motorists and a few technicians do not know that a CVT gearbox must be serviced with manufacturer recommend grade (viscosity) of CVT fluid. It is worth noting that CVT oil is different from Automatic Transmission Fluid (ATF) and the two fluids work differently. CVT fluid provides a small amount of friction to allow transmission bands work while ATF employs hydraulic pressure and friction inhibitors to help the gearbox work.
As such, you cannot use ATF to service a CVT gearbox. Ideally, CVT gearboxes should be serviced every 35,000 - 50,000kms. If you carry out periodical maintenance of your CVT gearbox with the correct fluid, you will enjoy trouble-free motoring in your Nissan.
HOW DO I CONFIRM A CAR’S MECHANICAL ISSUES?
Hello Paul, someone wants to sell to me a Subaru legacy GT at Shs6m. However, the alternator runs nonstop, thus over charging the battery. Could there be other issues for this car to be this cheap?
Kon. B.
Hello Kon, does the Subaru start and run? Take it to a garage for inspection by a qualified car electrician. A voltage and alternator tester can be used to confirm the status of its alternator.
You may need to replace the alternator since it may have a faulty regulator, which is not easy to repair because of unavailable spare parts. Occasionally, a wrong type battery can cause an alternator overcharge, especially in newer type vehicles built with battery control module.
To confirm if that Subaru is worth Shs6m, check the condition of the engine lubrication system. Get an engine compression test to confirm that it does not burn oil. Check the automatic gearbox too. A road test is a good idea to get a general feel. Also, rule out major accident repair.
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