Transmission fluid changes: partial vs full flush??

My new-to-me 2008 with AT has 85,300 miles. Already changed the timing belt (and good thing, too!) Now I'm scoping in on the tranny. I've read bits and pieces of the answers in several different threads for several different mileages, so I thought I'd start a new thread and collect all the wisdom here! :p

The oil on the dipstick is brown - about the same color and the engine oil, but not as thick. I have every reason to believe it's been changed at least partially at least once, because this was a rental until sold to the person I bought it from at 43,500 miles. And I don't believe it's been touched since then.

Looking at all the specs, I found Castrol Transmax Import Multi-Vehicle ATF, which (according to their web site) meets Type T-IV, JWS 3309, and GM 9986195 specs. It's available at my local auto parts store for about $20(US) per gallon. My planned usage will be trips in town of 5-ish miles one way (small town); occasionally I may have to take it to work, which is a 35-mile hiway trip. Air temperatures get up over 100F for several months (for a while, they don't go *below* 100 at night!), and the asphalt temps are much higher.

My thought was to do drains from the plug every month or so. I know that's only 2.2 qt in an 8 qt system, and it's not going to get every drop of old stuff out of it. But eventually it should replace most of the fluid, yes? Enough to make a significant difference?

I've heard bad things about a full flush - like pressure pushing O-rings out of place, or shoving little bits of stuff into tiny holes. I've heard there is a way to run the engine and shift through the gears with hoses running into fresh fluid, so you are continually pumping out the old and sucking in the fresh.

Should I just do partials for a while? Just until I replace 8 qt? Or for much longer?
Or should I do a flush of some kind? (I don't trust any shop in town to use spec'ed fluids!)

Ed

The one thing that's fairly consistent within the DIY community across the various auto forums is a big thumbs-down on 'power' flushes. And that would be any done using a pump other than the vehicle's own tranny fluid pump. For anyone who likes power flushes, you can stop reading this now.

You'll usually find 2 DIY camps on tranny fluid maintenance; one the drain-and-fill guys, and the other being the 'transfer' group. Transfer is done using (usually) one tranny cooler hose to change out the old fluid (after first draining and refilling the pan fluid). There is also a more involved version of this where both hoses are used: one to continuously supply new fluid, and the other directs the old fluid into a container.

I'm in the drain-and-fill group with my daughter's '06, and so far so good with that one. I swap 2 quarts every couple of motor oil changes, and this is a very fast, simple, and inexpensive bit of maintenance. I've always been a bit leery of the transfer method, but many folks have posted using it with no problems. Assuming there's no side issues with transfer, I don't know how much better/more effective it is than drain-and-fill. I think the only way to really find out would be to have a few before/after UOAs done by one of the labs. But that gets expensive fast, and I'm personally ok just going with gut feel, based on the look and smell of the fluid.

Oh yes, and there's a third DIY group that needs to be included as well. There is a minority group of guys who do nothing except check the fluid - no changes whatsoever. There is one fairly reliable guy on a van forum who says his van has 300K+ miles on the factory fluid, plus he says he tows with that same vehicle! So for anyone who's in the 'lifetime' tranny fluid group - carry on.

I remember changing the oil for the first time in my first car (1954 Chevy BelAir). I had to ask someone to show where to put in the new oil! And I was so surprised that I could see the dipstick through the oil. "Oh - *that's* what it's supposed to look like??"

Knowing that tranny fluid is reddish, and what's currently on my dipstick is neither red nor see-through, I am NOT in the "lifetime" camp. Especially not when (a) it's my wife driving this car mostly and I don't want her to have to deal with tranny problems, and (b) I don't want *me* to have to pay for tranny problems!!

So you think even at this point, a drain-and-fill every second or third oil change is okay?

Ed

Start with one drain-and-fill. The new and old fluid will probably combine fairly quickly. But in order to be sure of that, do a week of driving, and then start checking the fluid daily. If it looks the same on a few consecutive days, then it's fully mixed for certain. At that point you can decide, depending on how the fluid looks, if you want to do another round immediately. You can repeat the process until you're satisfied that the fluid quality is what you want. Once you're at that point, yes I believe somewhere around every couple of motor oil changes will keep it up to par.

I know this is an old post, but did you ever do the few quarts at a time change over on your Aveo? Did it work? Or did it cause issues? I want to do this same way myself, maybe faster though. Like as much that will come out, put back in, and keep doing it WEEKLY, not at oil changes, till it is as 'red' as the fluid can get. Then most if not all of it ,is changed out. Just wondered if yuo ever did it, if you still have the car, and how it went.

I thought you were replying to this thread:
http://www.aveoforum.com/forum/f108/...sh-done-22901/

No, I haven't done anything to it yet.
I should have a long holiday weekend coming up.
I fully intend to do it then.
Really. Honest! Cross my heart ....

Ed

Does your Aveo have a 'drain bolt' on the tranny pan? I cant get an answer to that question from anyone here,or online, for my 2006 Aveo.
And i dont know where to look to get an answer. There are so many bolts/screws on the lower part of the engine, I dont want to just open every bolt!
I wanted to do the open the drain bolt, get out 2 quarts or so, refill it, next week or a few days, do it again,and do it four or 5 times, till i have as red/pink fluid as I can get on the tranny dipstick. this Memorial Day Weekend, is a washout for us in the south, with the first storm,already,of the season coming in, it is already raining. BUT you are in AZ. Are you perhaps going to do your change this weekend?
Since I CANT get an answer to my tranny bolt question, I am going to get a 'transfer pump' and pump out 2-3 quarts through the dipstick hole,do it that way 2-3 times, and get out as much as possible. No crawling under the car, and it does the same thing, but it wont get out any metal if there is some attached to the bolt, IF there is one, and IF it is magnetic.

My 2008 has a drain plug. It is not magnetic. But there are magnets in the pan.
Attachment 11530
The answers are here in the forum. Spend time reading thru the many threads.
Not trying to be sarcastic or demeaning, but from your post I want to ask:
-- Do you know which is the engine oil pan and which is the tranny oil pan?
-- Can you tell which is the drain bolt and which is a pan bolt?
-- Do you realize that nobody on the forum has to respond to any question? No one here is a paid "Aveo Answer Man".

Good luck.

i have tried to reply to you 4 times, and i keep getting a notice that i cant post a quick reply for some reason. I am tired of typing, So ill try this one last time a SHORT one. Yes I know the difference IF I knew a drain bolt was there. it seems every year has an answer to that question, except the 2006. Seems each year is a different answer. I have even asked Chevy, and they wont tell me. They want the money i guess to change it out. I am not paying $200 for 'flush', I just want a simple drain, and if it has a bolt, i can do it myself. IF I dont have to jack it up. I see you jacked it up for that pic.

Did you start your draining,since it was up on jacks?? How much did you get out? I searched the internet and every year has an answer, for the drain bolt question, except for the 2006. So i dont know where to even look for one. IF the car has to be jacked up to get to it, I cant do it, i dont have a floor jack, and I am not getting under the car, with that tiny jack in the trunk. A simple question like this is usually answered. But after 4 tries, I have no answer. and each YEAR seems to be different. I dont know where else to ask/look for an answer, if Chevy wont even give me an answer.

I put the rear tires on ramps and the front on jack stands. That way I could run the engine and let the front wheels spin through the gears. I wasn't sure mine had a drain bolt either - but once I was underneath, the drain bolt was obvious.

You get a skoosh more than 2 quarts out of a single drain. After the first drain, I completely removed the pan to replace the filter - and discovered that removing the drain bolt doesn't drain all the fluid from the pan!! Knowledge that fell from the sky! Fortunately, I was at the other end of the pan at the time. But between the pan incident and the one time the funnel came out of the dipstick tube as I was filling, I have quite the pile of kitty litter in my driveway. :banghead:

After four drain-and-fill cycles, the fluid is reddish and clear. But I'm not personally satisfied I've got a high-enough percentage of new to old fluid in the mix. So I'll probably run another gallon (two drains) through at a later date. My work schedule won't give me time until August, though, and then it'll be time to change the oil and do my timing belt again.

Cheers!
Ed