Auto Service World
Feature   May 1, 2014   by Tom Venetis, Editor

Transmission Service

Traditional mechanical service giving way to more complex electronic maintenance

Transmission service and repair is the one service that vehicle owners dread. It is expensive, time consuming and sometimes the tipping point for some between continuing to own their current vehicle or buying a new one. Go into any wrecking yard and you will likely find vehicles that are in great shape but were abandoned because the owners did not want to do the needed transmission service or maintenance.

The challenge for service shops is educating vehicle owners on the need for regular transmission inspection and maintenance. Often, owners will neglect the transmission because problems never arise in the system until the vehicle is old; or they are told that today’s modern, highly advanced transmissions are ‘sealed’ units and never need to be opened or have the fluid changed.

For the moment, let’s first focus on the education aspect. What vehicle owners need to understand is that regardless of the transmission — be it an older, more mechanical system or one that uses complex electronics to operate — it is a system that must be inspected regularly in order to work properly over the lifetime of the vehicle. Just as you need to change your oil and filter and inspect the brakes, the transmission needs to be serviced periodically to avoid driveability issues and costly repairs.

The next thing vehicle owners need to be told about is that what they think is a transmission problem may, in fact, not be related at all to the transmission. Many technicians have stories of vehicle owners coming to them with an issue that they are certain is a transmission issue and are close to abandoning the vehicle because of it. The reality is that the issue is unrelated to the transmission. What do vehicle owners commonly mistake as transmission issues? A stuck fan clutch that makes the fan spin faster than it needs to and sounds as if the engine is racing. Poor vehicle acceleration is more often the result of poor fuel flow, a bad fuel pump or even an engine misfiring. A vehicle surging or bucking is more often an engine issue than a transmission issue and vibration while driving at high speed is often an issue with the wheels or driveshaft.

Sealed Does Not Mean It Can’t Be Serviced

One of the biggest changes with transmissions today is their growing complexity. Much of the complexity is driven by the need to improve both vehicle performance and fuel efficiency, says Dan Fenos, one of the principals with the Toronto-based Transmission Depot Inc., specializing in transmission repair and maintenance.

“It is all driven by fuel economy and that is why you have the seven, eight and nine speed transmissions,” Fenos adds. “I was doing some research and some are claiming that with the new nine-speed transmissions, you can have a fuel savings of up to 16 per cent. On one of the eight-speed, rear-wheel drive vehicles, you will see an 11 per cent increase over the first generation six-speed transmission. This is all being mandated by new government regulations for fuel efficiency.”

Along with the added speeds, today’s transmissions are also coming under increasing computer control in order to improve performance and make the shifting between the gears smoother for the driver. To better protect the system, many transmissions are becoming ‘sealed’ units in order to protect critical components.

This is where the confusion starts for many vehicle owners. The term ‘sealed’ suggests to many that the transmission system cannot be examined and that transmission fluid cannot be changed. Tony Stevkov, regional business manager at Richmond, Hill Ontario Mister Transmission (International) says that this has given vehicle owners the impression that today’s modern transmissions never have to be serviced. “Today there is less and less transmission maintenance service requested by consumers coming into our shops. This is because consumers believe transmission fluids are for life as the systems are ‘sealed.’ Transmissions that are ‘sealed’ units do not have the traditional dipstick and tube where you could check the fluid quality and fill it up through that tube. “

Stevkov explains in greater detail the kinds of changes happening: “More and more transmissions have switched to a sealed unit with the cover on the side, covering the valve body. Now there is a drain plug on the bottom of the transmission case and a cap with a dipstick attached, giving access to an opening to fill transmission fluid. General Motors, for instance, has moved away from placing the transmission pan on the bottom, which you would normally remove to drain transmission fluid. Toyota’s new Sienna vans have special drain and fill plugs with no dipstick at all. Chrysler has switched to a dipstick tube design, but with no dipstick as well.

“The trick is to use a universal dipstick tool that has a series of lines with corresponding numbers. The requirement is to have a scanner hooked to the vehicle, with the transmission fluid temperature displayed in the vehicle data. The level on the dipstick has to be in accordance with the temperature of fluid. So, if the scanner registers 60 degrees, the fluid level on the dipstick has to be 60 degrees. That is how you know the fluid level is accurate.”

Even changing the transmission fluid has become more complicated with vehicle manufacturers mandating specific fluids be used with their transmissions.

“When people say transmission fluid is for life, they mean fluid is the life of the transmission. If you want your transmission to last longer, you must replace the fluid and filter,” Stevkov explains. “Today’s transmissions rely heavily on computer controls. Manufacturers have eliminated things such as bands and clutch-to-clutch application has increased; this requires specialized fluids. When these clutches apply and release, they have a tendency to make odd droning noises or produce shudders; some can be quite abrupt.

“What manufacturers will do is modify the transmission fluid with frictional properties to slip the clutch on application. To reduce shudders or drone noises, we engage quickly and stop shuddering immediately. There are also custom-tailored fluids with unique additive packages specific to those transmissions; this will vary depending on the design and purpose of the transmission.”

For example, Stevkov says Ford and Toyota have particular fluids for their particular lines of transmissions. Honda has a high-frictional property transmission fluid that helps slide the clutches to make the transmission operate and the car drive smoother.

“However, if you were to take that fluid out and replace it with a fluid for GM, you will find you have a harsh shift, which may concern the driver.”

Today’s Fix Will Likely Be Electronic

Where the greatest change has happened with transmissions is the increasing use of computer controls. This has shifted the work of technicians away from merely mechanical servicing and maintenance to more on computer diagnostics and flash reprograming of the vehicle’s ECMs. Tansmission Depot’s Fenos says that today’s transmissions are requiring technicians to become computer experts as many transmission issues and problems are now fixed with software updates or scanning the system, to find problematic solenoids for example.

Fenos gives an example that on “some new nine-speed transmission they can have up to 10 solenoids and you have to have the tools to diagnose the system to find the faulty solenoid.”

He also says that because of the complexity of the systems, it is going to be very important that technicians spend time with customers educating them on how these transmissions work and what is needed to maintain them.

“I love to educate my customer,” Fenos says. “I will show them the scan results on their transmission because the customer likes and very much wants to be part of the repair. I will sit down with them and show them how I will reprogram their system.”

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