Hi Guys,
I have a 2004 Subaru with 140 thousand miles on it. I have no problems with it at all. Some people tell me to change the transmission fluid and filter, while other people say," If it isn’t broke, don’t fix it". Any ideas on this? I bought the car used and never did anything to the transmission. I know “I” put at least 50,000 miles ( not sure) on it.
This is more of a IMHO answer but if you are planning on keeping up to 200K and beyond I would seriously considering doing some preventative upkeep. Unless you are just planning on driving it until it drops. Transmission issues are a drop the car situation IMHO. Hmm, maybe this thread belongs elsewhere. I just can’t imagine where., it’s on the tip of my tongue. 
Believe me, if that has never been done up to now, it certainly needs doing. My saying, “Properly maintain your car before it gets broke and then you have to fix it.”
Find the transmission dipstick and check to see if the fluid level is full, and whether the fluid looks burnt or discolored. If yes, then changing the fluid and filter would be a good thing.
If not, the worst case scenario is that flushing the transmission will dislodge a lot of gunk and uncover a lot of problems. But if that happens, your transmission was living on borrowed time anyway, and you would experience problems sooner or later.
Take it to an auto mechanic you know and trust, or get a referral from someone you know, and have him/her check it out and have him/her tell you what they think.
My Dad claims he never had that done on any of his cars and that when they start tinkering with stuff that’s when something goes wrong, of course I’m not talking about stuff like brake pads or tires. He might have a point he did the bare minimum maintenance on his Camry and it had over 300k miles when he got rid of it, though it still ran, if it ain’t broke don’t fix it.
I’ve wondered this myself. While I wait to see if any of the names I recognize as SDMB’s Car Experts show up, I found a reasonable-looking article that acknowledges that there’s some debate involved.
Don’t do a flush, but open the draincock and release and catch what comes out. Measure it and pour back in the same amount of new fluid.
Thanks for your thoughts ( all of you). I do check the fluid and it looks good. The car doesn’t smoke and there are no leaks. It runs great and I’m not sure what to do.
“Thudlow Boink” Thanks for the article. It seems like the people who will make a buck from it say I should do it every 2 years. That seems like a bit much.
The shops hear in south eastern PA want about $90.00 to do it. If it needs to be done-that’s okay, but I don’t want to throw money away.
On the other hand. I’m 68 and I don’t want to buy another car if I can help it
Yeah, replacing the fluid and filter on a tranny every two years is high way robbery. As long as I’ve been driving cars, the owner’s manual has (had?) a specific mileage interval for that as routine maintenance
I change the AT fluid once every couple of years on my vehicles. Well, it’s not really a fluid change; I simply drain it and refill, which (I think) gets most of it.
Not sure how correct this is, but I have heard that, if you have lots of miles on an AT and you have never changed the fluid, then changing it could be a Bad Thing. I am not sure why this would be the case, but I have heard it from enough people that it makes me think there could be something to it.
I’ve got a 2004 Impreza, it actually has 2 trans filters. And while your at it the AWD ‘transfer case’ has gear oil, so might as well change that. And the fluid in the rear end. Subarus!
it probably gets about 1/4 to 1/3 of the fluid.
if you change the fluid and your trans takes a dump, it was about to take a dump anyway.
I worked over 40 years as an maintenance Engineer. We had a saying. You will pay for maintenance one way or another. Either by doing the preventive maintenance in a timely and retune manner or you can pay for repairs later.
While there are some situations where “if it ain’t broke don’t fix it” makes sense, it is generally very poor advice when it comes to maintenance, especially of items that are expensive to repair. Do the people who say that have the same attitude about engine oil changes? Why change oil if the engine still runs?
For a modern automatic transmission, every two years is probably overkill, but an interval of 50-100K miles (depending on some variables) would be wise.
What does the manual say? By and large, a whole lot of highly paid engineers and technicians have put together a schedule to keep your car running well. Follow it and you’ll likely be fine. FWIW, I figure spending a few bucks on fresh filters and fluid is way less expensive over the long term than replacing a whole transmission or engine because you thought you’d save a few bucks.
And almost anything that causes your car to stop running will be expensive to fix. (There’s really no such thing as a cheap and quick fix for a transmission failure.)
Several mechanics including a transmission expert have told me that flushing the transmission fluid is a problem. What they said was that it stirs up a lot of gunk and pumps it through the components. That made some sense but other sources like yours and this one, Does “Flushing” a Transmission do More Damage than Good? still dither on the subject and say check the owner’s manual. Even draining the transmission first is going to leave some gunk in there anyway. Automatics are pretty complicated devices, just looking at a simple animation of how they work isn’t going to reveal all the seals and clutch mechanisms in detail. Just considering how long modern transmissions can keep going for hundreds of thousands of miles, often with no service at all, it doesn’t seem like there’s a simple answer for this question. The amount of gunk in the fluid and how well fluid maintained functionality is going to be all over the place, car by car, model by model, problems after flushing might have occurred just the same if the fluid was drained.
In the end I’m in the “don’t fix it if it ain’t broke” group. The only thing that turned out to be actually wrong when I’ve had transmission service in two cars was a sensor, nothing in the transmission mechanism itself.
You should do the full service of the transmission on the schedule recommended in the manual. DO NOT do the transmission flush, that is a short cut performed by shady quick lube places.
Usually a full service consists of draining the fluid, dropping the transmission pan, cleaning the magnet, and replacing the filter that is inside the pan. About 50,000 miles or so. For a do-it-yourself type person it is only a little more complicated than changing your oil.
Don’t do the flush, it is a cheap shortcut and a bad idea.
I disagree. when you drop the pan, you only drain away about 1/4th to 1/3rd of the fluid. the rest of it is sitting in the torque converter. A flush completely renews the fluid. An in some cases (like the 5R55W in my Ranger) where the factory service procedure is to flush the old fluid and not change the filter. Takes 12 quarts of Mercon V while dropping the pan would only change 3-4 quarts.