Do I need to change the transmission fuel and filter?

I just had my oil changed. When I picked up the car, the mechanic said I need to have my transmission fluid and filter changed. $150.00

He said I have to do the fluid every 25K miles and the filter every year. I have 42K miles on the car and no transmission problems.

I have not done this yet. Do I really need to do this? or does he have a boat payment due?


What type and year car? $150 is cheap for this service in my area. But 25,000 miles seems a bit early . . . what does your owners manual say about this maintenance? How often does the manufacturer suggest as the change interval? Rocketman

The answer to your question can be found in your glove compartment.

If you look at the manufacturer’s maintenance schedule (contained in either the Owner’s Manual or in a separate booklet with an appropriate title), it will give you very comprehensive information on questions such as this. Since every make of car differs on points like transmission maintenance, you are far better-off taking the word of the manufacturer, rather than random suggestions from strangers who did not build the car.

Transmission fluid should be changed periodically. Check your owners manual, it’s spelled out clearly in there what the interval should be. Also…some vehicles don’t have filters…this is also spelled out in your manual.

Well, it’s a 2001 Mazda 626. I checked the owner’s manual. I checked it 3 times and this is what I learned. Apparently the entire car should be rebuilt every two years (including all nuts and bolts on the chassis and body), but not one mention of when I should change the Transmission fluid or filter.

Well, it’s a 2001 Mazda 626. I checked the owner’s manual. I checked it 3 times and this is what I learned. Apparently the entire car should be rebuilt every two years (including all nuts and bolts on the chassis and body), but not one mention of when I should change the Transmission fluid or filter.

I own a Mazda MPV and the owner’s manual doesn’t speak to the filter or ATF change. I think Mazda is remiss in not suggesting a filter and fluid change in the maintenance schedule.

I settled on 30K mile intervals, to coincide with the 30/60/90K service for the car anyway. I would go ahead and do it, and then do it again at 60K miles, and keep it up at 90K, etc. That is safer than assuming the fluid, filter and gasket is good forever, which appears to be Mazda’s line. Go for pan drop, gasket, filter and ATF change, not a flush.

As noted, do it according to the owner’s manual. I would suggest that if the owner’s manual does not say then about every 50,000 miles or 5 years, which ever comes first is good for a minimum.

The service he is suggesting (change w/ filter change) is IMO preferred to the FLUSH which seems very popular for getting boat payments.

I recommend to my customers a pan drop and filter/fluid change every 25k. 25-30k is ok. I wouldnt flush it unless the fluid is contaminated. I see way too many broken transmissions cross my bench on a daily basis due to improper or lack of servicing. A filter kit and fluid normally wont cost more than $40.00 so why not do it??


I think this might be the same transmission that is in the Ford Escape. Seriously. (Actually, I just checked, and it IS the CD4E transaxle. I’m not kidding).

I mention this because Ford Escape transmissions are notoriously fidgity about transmission fluid. Ford specifies 30,000 mile intervals for the fluid, and 150,000 miles for the filter. I looked into doing the filter more frequently, but the transmission filter on this car is really buried.

I scoffed at the 30k mile interval, and when I got to 50k, the transmission shudder was so bad, I had to change the fluid.

In the case of this specific vehicle, I think 30k miles or less would be prudent.

By the way, I did the fluid change myself. One dozen quarts of Mercon V. Nowhere near $150…

What he is recommending is a very good idea. You have no transmission problems NOW, but when those problems develop later due to not changing the fluid then it’s a moot point. That’s closing the barn door after the horses got out.

Also, a vehicle can run fine with a partially clogged fuel filter. That filter will also shorten the fuel pump life because the pump is having to work harder.

Totally agree! A friend of mine has a Mazda 626, and maintained it BY THE BOOK over the years. He now has a slipping transmision and is faced with a $2000 plus transmission overhaul at 150,000 miles. Has Mazda specified periodic drains & filter changes, the transmission would have been OK.

It isn’t just the CD4E that is fidgity… Ford transmissions in general seem to be a bit more fidgity about transmission fluid changes from my experience. That said, if maintained by the book (30k fluid changes on many), problems seem to be pretty rare (now that the true lemon transmissions like the AXOD-E are gone)…

I’ve got a Taurus with the AX4N. I’ve swapped out the filter once myself (not a hard job, just messy) and had it done once by my mechanic. If you do it yourself, its cheap. And fluid isn’t expensive. But here’s what I suggest, rather than fork over that much money.

Go to Harbor Freight or any local parts store and get a cheap hand pump with flexible tubing. I suggest Harbor Freight because they sell one for $3 that works perfectly well for this… You can use it to suck as much fluid up the dipstick for the transmission as possible. Every year, I suck up as much as possible and replace it with fresh fluid. Usually I can get about half the total transmission fluid out this way. It doesn’t get any out of the torque converter, but you get about a 50% change easily and cleanly. When the pan is as dry as possible, you can then drop it more cleanly by hand (it doesn’t spill everywhere) if you want to change the filter and clean out the pan.

But here’s the kick of doing it this way: You don’t get a 100% change like you’ll get for that $150. But you do it more often for about $15 each time. So after the first time, you have 50% new fluid. The second, it’s 50% new, 25% one year old, 25% two years old. The third, it’s 50% new, 25% one year old, 12.5% two years old, 12.5% three years old. The fourth it’s 50% new, 25% one year old, 12.5% two years old, 6.25% three years old, and 6.25% four years old. And so on…

See, it will never be 100%, but it’ll be close… 75% of the fluid will be one year old or newer. And you can even go to 6 month intervals, if you want, to get even cleaner fluid. If you do that, your fluid will always average out (by volume) to be just 6 months old. That is SERIOUS overkill. If you do this just once a year, your fluid, by volume, will average out to be just 12 months old. And the savings will be significant…

Hi , consider looking at the trans pan and see if it has a fluid change bolt on it for changing the fluid- just like engine oil pan has. If so you can change the fluid in the pan just like the oil. I drain my trans pans now with every oil change as it keeps adding fresh fluid and cheap a ew quarts of new fluid each time. So far trans in several of our cars act like new, so must be doing some good. On some of our cars i have dropped the pans changed the filters and added a drain plug to the pan too so now i can drain these pans. Why US car makers did not add drain pugs to trans 30 years ago i can only wonder if it was to sell more cars as trans gave out too soon…

A lot of makers have actually taken drain plugs away…

Too many Jiffy Lube employees were draining transmission fluid instead of oil, then adding even more oil to the oil pan. Transmissions were running VERY low on fluid and engines with WAY too much oil… recipes for disaster. Without a plug that isn’t a problem. :slight_smile:

I did roughly what you describe, but over a 3 day period. I sucked out the fluid using a Pela 6-litre extractor, from the top as you suggested, then added in about as much Mercon V as I took out. Drove it around for a day, and repeated the procedure. Then I drove it around one more day and did it one more time. The transmission holds 10 quarts, and I used about 12 for this procedure.

I felt that one complicating matter with this was the change in ATF type. When I got the car, in 2002, the manuals all said, “Mercon ONLY.” However, shortly after that, Ford quit licensing Mercon, and all you could get was Mercon V. I wasn’t sure how compatible these types were, so I decided to err on the side of caution and get as much as the old stuff out as I could. I obviously didn’t get ALL of it out, but I did get a high enough percentage, I think.

I think the correct answer is you can mix Mercon V and Mercon as much as you want.

My transmission works perfectly. Now, if I could just do something about this spark plug ejection…

Make sure that the proper transmission fluid is put back in. I ALWAYS change the filter when I change the tranny fluid–sorta like an engine oil and filter change. The tranny kits usually include a pan gasket and filter. This is another area that you don’t want to overfill with oil or fluid. A good independent shop will do you as well as a dealer and, in many cases, a heck of a lot better than a ‘chain’. You have to drop the tranny pan to get all of the old fluid out, though some fluid will remain in the torque converter. Flushing is not necessary unless the tranny fluid is really dirty, i.e.: looks like black coffee. Then a flush may be necessary but only if there is a lot of brownish-colored flakes in the bottom of the fluid pan. That’s a big reason to replace the filter–it’ll catch any left-over stuff that was left in the torque converter. While the fluid pan is off anyway, why not change the filter? You’re there anyway so why not “while I’m at it, I’ll change the filter”. Cheap insurance as opposed to a transmission replacement. While I’m at it, I open the cooling lines and run compressed air through them to ensure that the cooling lines are not obstructed.

On my 2002 Sienna, I pull the tranny drain plug which lets 3 quarts drain out. Book says it is 5 quarts total. I have done this several times, but I add synthetic. So, it is getting to be mostly synthetic. My vehicle has heavy duty towing package, which I am guessing includes heavy duty cooler. Anyway, the fluid has never changed color. I now have 136,000 miles, and no transmission problems.

Toyota told me it’s only filter is a screen, not a true filter like you guys are talking about.

VWs are the same way. They use a syn fluid and claim it “lasts forever”. However many posts on disagree! Dealers will change it if you insist, but for $300, fluid available only at dealers.

Something similar going on for antifreeze fluid, also “lasts forever”.
Seems there is a marketing push at many brands to have less regular maintenance, as that is perceived as “better”, and sells more cars.

My advice: change Trany fluid and filters, and antifreeze on a regular schedule, but in any case not beyond 50k miles.