BACKYARD MECHANIC: Change transmission oil when recommended

Hey there, time traveller!
This article was published 06/05/2011 (5332 days ago), so information in it may no longer be current.

QUESTION: Regarding my 2005 Honda Accord six cylinder, some advise not to change the transmission oil if it’s never been changed as it will actually damage the car. It has ll5,000 kilometres on it and the transmission fluid is a light to medium brown but doesn’t smell burnt. Even the Honda dealer suggests changing the fluid when they are asked.

What is the correct action, to change it or not? Does it matter if the fluid is dark?

ANSWER: The service manual maintenance schedules for your Accord (they should also be shown in the owner’s manual) show that if the vehicle is used for normal light-duty service, the first recommended transmission oil change is at 192,000 km or about seven years. The next would take place at 336,000 km.

While a few Canadian vehicles may be operated in light-duty conditions, most Canadian repair shops follow the severe conditions recommendations shown in the manuals.

If the vehicle is operated in what they call normal “severe” conditions such as short-trip driving, towing, high heat or extreme cold, then the first recommended change is at 96,000 km or three years (the time frame is especially important if you are towing). The next change would be at 144,000 km, next at 192,000 km and another at 240,000 km.

Your vehicle is nearing the time interval for light duty and past the mileage for severe-duty oil changes. It wouldn’t harm it to change the oil. Changing oil will not damage a good transmission as long as the correct replacement oil is used. As for the brown colour, it’s normal for most transmission oils to become a brownish red after being used for some time.

When looking at the oil, look for metallic flecks that would indicate either aluminum or bronze — these will be very small and indicate a bushing wearing. If there are small black flakes or particles, these are clutch plate materials. Both of these are cause for concern if there are a large amount of the particles, but there isn’t a problem if the oil is brown without other debris or particles in it.

QUESTION: I have a 2002 Civic with 54,000 km. The fellow at my service department says I should get a new timing belt because of the age of the car. Is this a prudent thing to do?

ANSWER: Replacing a timing belt at the recommended mileage intervals is extremely important because on many engines, if the timing belt fails, the engine valves will hit the pistons and do severe damage to the engine.

I looked at the maintenance schedule for your car and it shows the timing belt should be replaced and the tensioner and water pump inspected for wear (they operate with the timing belt) at 96,000 km if the vehicle is operated at temperatures above 43 C and below -20 C most of the time. If your vehicle is operated mostly between these temperatures, as I am sure it is, then the timing belt should be changed at 110,000 km.

There is no time interval for changing the belt, but the rubber belt can harden with age and fail even if the change mileage hasn’t been reached. There are many vehicles that are older than yours still operating with the original timing belt, but your service department technician may be basing his recommendation on a visual inspection of the belt. Cracks or frays in the belt are indications it should be changed.

Any timing belt that has engine coolant or engine oil leaking on it should also be changed, regardless of mileage. The belt breaks down prematurely when exposed to these chemicals.

Without looking at the belt, I can’t confirm the repair shop’s recommendations, although they do seem reasonable. You don’t want a belt to fail. On some vehicles, the timing-belt change recommendations are at 80,000 km, and I’ve even seen them as low as 30,000 km, although this is rare.

Replacement belts may have a longer change interval, as belt-construction technology is constantly improving. Some vehicles that needed the original belt changed at 100,000 km will need the replacement belt changed after another 160,000 km. Each model is different, so be sure to check on this with the service department. If they don’t have any information on this, continue with the original recommendations found in the owner’s manual.

Jim Kerr is an experienced mechanic, instructor and member of the Automobile Journalists Association of Canada.

kerr.jim@sasktel.net