Ask the Mechanic: Should I change the gearbox in my Nissan Serena?

What you need to know:

After that, the car picks up and accelerates well but has the occasional jerk effect when I move my foot from the accelerator. I have had the system computer diagnosed, changed the fluid and serviced the gearbox, but the problem persists

Hello Paul, I have a 2014 HFC26 Nissan Serena that has a shift delay. I have had the car for a year, but more recently when changing from parking (P) to drive (D) or drive (D) to reverse (R) there is a four-second delay. After that, the car picks up and accelerates well but has the occasional jerk effect when I move my foot from the accelerator. I have had the system computer diagnosed, changed the fluid and serviced the gearbox, but the problem persists. Do I need to change the gearbox? Are there good Nissan mechanics you can recommend?

JPM

Hello JPM, do not rev the engine in an effort to speed up the engagement of the transmission. That could do damage. The problem is likely to be most noticeable at the first start of the day, and that is also when the risk of damage is greatest.

The delay problem is not uncommon, often because of poor maintenance or exceptionally high mileage (was your Serena a taxi?). The root problem is usually inadequate transmission fluid flow/pressure. The reasons for that can range from lack of fluid to very old fluid to the wrong fluid to leaking seals to clogged filters in the box to detritus in the torque converter to a defective pump.

A specialist service should know that and be able to find and fix the fault. They should also have the necessary equipment to make an otherwise quite complicated process quick and easy, especially for draining and flushing old fluid and any debris in the torque converter. Ask your mechanic what he “serviced” on your transmission.

There is much more to properly servicing an automatic transmission than simply topping up or changing the fluid, and it is more important to find an expert on automatic gearboxes than an expert on your particular make of car. I cannot recommend a specific agent, but as automatic gearboxes are now so much more numerous in Uganda, experts are easily available.

As a test guide, if they do not have a special machine for flushing torque converters, be cautious, if they do have one, be encouraged. And do they know the difference between imt, AMT, CVT, TC and DCG automatic boxes?

Meanwhile, wait patiently for your transmission to engage, but do not wait to have the delay problem well repaired. So far you probably do not need to buy a new gearbox, but that could soon change if you do not act promptly.

For the consideration of all owners of automatics, the recommended fluid change interval is commonly 50,000kms and regular expert maintenance more than doubles a transmission’s life expectancy compared with service neglect.

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