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Transmission fluid flush?

My local Mazda dealer recently recommended that I have my transmission fluid flushed and replaced. A friend who is a car sales man has frequently told me not to mess with the transmission fluid. Who is right here? (The dealer says it “smells burnt” but the engine has never been over heated…)

Car owners who want to avoid transmission failure as the vehicle ages will change their transmission fluid–and filter, if so equipped–every 3 years/30k miles (whichever comes first). You have not told us either the model year or the odometer mileage of the car, but if the fluid has not been changed within this time/mileage timeframe, you would be well advised to do it.

That being said, if a “flush” is done by someone who is not truly expert in transmissions, damage can be done. What will not cause damage is a fluid change, rather than a flush.

Take the vehicle to an independent trans shop that has been in business for at least 3 years, and tell them that you want to have the pan dropped (to clean out accumulated debris) and the fluid changed. Then, repeat the process on the 3 year/30k mile schedule in order to preserve the functioning of the transmission.

DO NOT go to AAMCO, Lee Myles, Cottman, Mr. Transmission, or any other chain operation unless you want to be told that you need a new transmission–whether you do or not.

Overall, the dealership is correct about the need to service the transmission, but there is no need to have the service done by them. And, if the fluid has a burnt smell, you had best get that fluid changed a.s.a.p. if you want to save that transmission. Your friend–like virtually all car salesmen–has little knowledge of things mechanical, and he should be ignored on the topic of car maintenance.

Automatic transmission fluid should be changed. How often it should be changed has nothing to do with the engine overheating. Transman18, the recognized expert on this forum, recommends changing fluid every 30k miles.

The dealer is pushing a flush because they bought a flush machine which makes them lots of money. I’ll bet your Mazda owners manual doesn’t recommend a flush.

Flushes can be risky because they don’t allow the transmission filter to be changed, nor the sediment in the pan to be removed. Many transmission flush machines use a generic fluid with additives added for specific vehicles - a recipie for problems.

You’re better off using the age-old method of dropping the pan, replacing the filter, cleaning the pan, and replenishing with the exact fluid Mazda calls for. While it doesn’t drain the converter, it is the method recommended by the manufacturer and it’s worked for millions of vehicles for many decades (until these profit-making-flush-machines came out).

If your MPV’s owner’s manual is like my 2001 MPV’s, you can’t find any info on when to change the fluid. I found at 65K miles that the fluid is not a “lifetime” fluid because it was turning brown and smelled burnt. Mazda conveniently says nothing about the transmission fluid change.

I put my MPV on a 30K mile schedule. My mechanic does the pan drop, filter change, and uses a transmission fluid exchange machine to finish the job. So far, the Mazda has 135K on it with no problems. A plain pan drop and filter change would be fine, too. My AT uses Dexron III, which is a relatively generic and easily available fluid to buy.

I would recommen this same regimen to your MPV.