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3.6L 6 speed trans flush advice please

46179 Views 71 Replies 23 Participants Last post by  SilverSport
09 malibu 3.6L 6 speed with 50,000 miles on it. I was reading the owners maual and from what I understand the fluid is "lifetime" unless you fall under the severe duty catagory and then you need to change it at 50,000, is this correct?

I don't think I fall into the severe duty but I think I would like to change the fluid as a preventative maintenance thing, don't think it can hurt can it?

So if I do this do I need to flush it or can I drop the pan and drain and add new fluid? Also is there a servicable filter I need to change?

Any advice with this would be much appreciated,
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Thanks for the advice jes2. Yes I have also read about the flush causing problems in transmissions, but mostly in high mile trannys that haven't been serviced.

I would like to just do a pan drop and fill since it should be pretty simple to do myself. I have to do that on my mom's civic, honda doesn't recomend flushing at all and figured I might as well do one on woman's car at the same time.

Was hoping someone had done this before and could share some advice on what all is involved.

Most people follow mfg. suggested intervals for tranny maintenance which is mostly too late IMO. You need to check your oil often to see any discoloration and smell. If it si dark and smell gas, it is time to change it regardless of your mileage. I find Chevy's 50K interval too late. I believe this should be 30K.
From what I understand of the owners manual reading the maintenance schedual chevy only recomends a 50,000 interval if you fall under the severe duty catagory. Otherwise they don't have any recomendation of tranny service, lifetime fluid. I thought I was doing good wanting to do something at 50K.

Well I'm around 50,000 and I would like to do some kind of maintenance, either a fluid drain and fill or a flush. I will check the color of the fluid tomorrow to see how it looks.

So there is no filter that needs to be replaced? I see one listed at parts stores. Can I flush the tranny at home by unhooking a cooling line? Or is a drain and fill good enough?

Thanks for the advice guys.
Looks like a drain and fill it is then! I will start doing a drain and fill every 20-30K miles to keep a little fresh fluid in there.

On a side note, my mom has a honda civic with 30K and honda does not recomend a flush ever, just a drain and fill and no filter to change.

Thanks for all your help guys!
Is there a washer or seal on the drain plug that I need to replace when I do this? I am also going to be changing the trans fluid in mom's civic and there is a crush washer that needs to be replaced so this is why I ask.

Wow this thread sure went to crap since I posted it!

I did a lot of research when I was looking into this, I am not an engineer or a mechanic but do have experience with auto maintenance.

I do not believe in "lifetime fluid". Yes it can be lifetime fluid when eventually the tranny fails the fluid is also done. I don't care what any engineer or mechanic says, no fluid is lifetime. I can run the same engine oil and my engine will probably go for 100,000 miles without problems but then the engine will die eventually. Would that be called "lifetime" engine oil? Because the oil lasted the whole "life" of the engine. Chevy calls for fluid changes for severe duty, so there is absolutely NO reason why the fluid can't be changed at regular intervals, NONE. If you want to believe in "lifetime" fluid than that is your choice, of coarse the fluid is going to last the lifetime of the tranny, but now you have to wonder what defines the lifetime of the tranny, and if changing the fluid would have extended the life of the tranny.

My 6T70 has a dipstick and a drain plug. It got a fluid change. It will continue to get fluid changes. And I will guarantee that by changing the fluid it will get the most life out of the tranny possible. Changing the fluid isn't going to hurt the transmission, why would chevy put a dipstick on it if the fluid level was so complicated? They wouldn't. Now as far as the engineers that decided they would make the choice for me that I don't need to change the filter, well in my opinion they are very wrong and should be paying for new transmissions when they fail. I could never change my oil filter when I change the oil but eventually it will clog, just like the transmission filter will eventually which will lead to transmission failure. If a filter is needed it should be replacable, period. No engineer should be able to decide that my filter never needs to be changed, why even have a filter then? Basically the engineers are putting a limit to the life of the tranny. If I chose not to do maintenance on my car that is my choice but when an engineer decides for me that a filter that should be changed is not changable that is wrong.

Trannies are the weak links in most vehicles, they need to be serviced to get the most out of them.

In the end we are all responsible for our own vehicles and can decide what we do to them as far as upkeep, unless engineers decide for us. But there is no such thing as lifetime filters and fluid.
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trans engineer-explain something to me please.

Why would chevy say that the fluid needs to be changed for severe duty but then you say that changing the fluid is a bad thing? How can preventative maintenance be a bad thing, no matter if you car is severe duty or not? If it's required for severe duty driving then it won't hurt anything to change the fluid in normal driving. It's a sad day when a car company decides to chose for me that I can't change fluids and filters that need to be changed. You don't have to be an engineer in order to realize that if a filter is needed that it will eventually clog and need to be changed, or it will lead to trans failure-but the filter lasted the life of the trans. You also don't have to be an engineer to realize that no transmission fluid is lifetime, they break down and lose the properties that make them work, which will lead to trans failure-but the fluid lasted the life of the trans. Chevy decided for us that we shouldn't change the fluid or filter and it will last the lifetime of the transmission. Of coarse it will last because once it fails the trans will also so yes, the fluid lasted the life of the trans.:rolleyes::rolleyes::rolleyes:

You can say the same thing as far as engine oil goes. I can never change my oil and filter, and I will personally guarantee it will last as long as the engine does. Althought the engine will not last as long as if you were to change the oil and filter.
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That brings up a very good point in my mind.

If the temperature of the transmission, not necessarily the engine, is critical to proper filling, where's the transmission temperature display so I know when to check the level and adjust it as necessary? Why is the car now the expert and not the owner? I asked the car but it didn't answer.
In my opinion GM made the decision for us that we don't need to do anything to the transmission, just run them till they fail. Which is very wrong to me. They don't give you a way to check the fluid properly due to not being able to tell the temp. They tell you not to change the fluid. They don't give you a servicable filter to change. They don't make filling them easy in any way. They took out anything good for the transmission. It's like having a kid and never taking them to the doctor for checkups until they die. But claiming their "fluids" lasted the life of the body. Just drive it till it dies, cars have become disposable items. If they last five years with no maintenance then the manufacturers are happy, everything after that is all proffit for them.

Why make fluid changes easy? That would stretch out the life of the trans. Which means they don't make thousands of dollars on you for a trans replacement.

The whole thinking of lifetime fluid and filters is very wrong. And I understand that GM doesn't want some people messing with the fluid because if they mess up it will lead to failure, but for them to take that away from me and shorten the life of my tranny isn't a choice they should be allowed to make. And then make false claims of lifetime fluid and lifetime filters.:eek::eek::eek:
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Checking the fluid level is important to keep the trans in good shape though. Doing it properly is what is going to keep it that way. The fluid temperature needs to be in a certain range to properly indicate the level, so yes the fluid temperature is important. What's to say the fluid level was correct before draining it? For how expensive a trans is to overhaul it is better to air on the side of safety. What I there was a leak that the owner didn't see? There are to many risks to do it as simple as drain and fill unless you know for sure it was fine before.
I agree with what you are saying. The problem is GM doesn't agree with you. That is why they make it so hard to check the fluid. Also they state in the owners manual that we don't have to check the fluid. They say we don't need to change it or the filter. Don't need to worry about it at all, just run it till the tranny pukes. This is a huge design flaw by GM.

You bring up some good points about drain and fills, the fact that if you measure what you take out it still might not be right, due to leaks and what not. But you also have to consider GM says not to worry about the fluid until there is a problem. So if there is a leak it will drain all the fluid unless you realize it and then kill the tranny. So in reality it doesn't matter if it was leaking or not, because GM tells us not to worry about it, and doesn't give us an easy way to check the level to see if it's leaking. Sometimes you won't notice a small leak untill it's to late. To the average person this sounds great, never have to change fluid, never worry about fluid level, etc. But to anyone that has any mechanical knowledge this is a joke.

You say there are to many risks to doing a drain/fill and using the fluid that comes out to measure how much to put back in. You are correct that it's not the right way to do it but it's still better than just leaving the old fluid in and never changing it. If there is a leak it doesn't matter if you change the fluid or not, either way you still are going to be short. And GM has decided not to give us an easy way to check the fluid level and they specifically state in the manual not to worry about the fluid unless there is a problem. Which a lot of the time if there is a small leak you will not notice it till it's to late.

Thanks GM, for a crappy design.

You sound like you work at a dealership or are a mechanic? If so is there a way for the average person to check the level? Mine has a dipstick, but as you stated you have to check it at a certain temp. So is there a way to tell the temp to check the fluid? I know honda says to run the vehicle for 20 minutes and then check fluid to get the right level. Is there a time to run the car to get temp to right level? Or some other way to tell the temp to check the fluid? Thanks
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I don't agree with GM saying the fluid never needs to be changed, but there isn't anything that says in the manual stating the fluid should never be changed. I have changed my fluid out at 60K and did not like how the fluid looked, it wasn't burnt but dirty from friction material. I have not had a single issue since, in fact it seemed to shift smoother than before. I am saying it is important to be sure the fluid level is correct because that is what will cause it to fail. I t is better to be safe than sorry. Yes, I do work for a dealer, but that doesn't mean I agree with everything I read. For the 4 cylinder owners it is very much a pain to check fluid level, and I hate it. For the 6 cylinder owners it is much easier since you have a dipstick.

The fluid range on the dipstick is also the operating temperature of the trans lowest being a certain temp and the highest mark a certain temp. Best way I can say to check the fluid level is drive it for 10-15 miles to be sure it is up to operating temp then check it on level ground. I don't agree with how things are done anymore, but there isn't anything I can do about it. I think it is more a design to keep the average owner who has no idea what they are doing from messing with their car, but the issue that causes is they follow what the manufacturer says to do.

I still stand by the older standards and don't follow the oil life monitor and change my fluids as I see fit. I have payed for the car and it is my responsibility to pay for repairs when it goes out of warranty, so I am going to take care of it in my way. The other thing is most cars end up falling under severe service in a lot of the climate regions, which is the other reason I find it necessary to change the fluid. All I was trying to saying in my previous posts that it is important to be sure the fluid level is correct to save from the issue of a bad trans later.
Thanks for your advice.
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