•  
    Results 1 to 6 of 6

    Thread: Transmission fluid changes: partial vs full flush??

    1. #1
      Should I keep it? EdNerd's Avatar
      Join Date
      Feb 2016
      Location
      SW AZ
      Posts
      52
      Thanks
      1
      Thanked 1 Time in 1 Post

      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!

      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



    2. #2
      Almost time to do my timing belt
      Join Date
      Aug 2012
      Location
      Northeast
      Posts
      1,231
      Thanks
      3
      Thanked 89 Times in 81 Posts
      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.

    3. #3
      Should I keep it? EdNerd's Avatar
      Join Date
      Feb 2016
      Location
      SW AZ
      Posts
      52
      Thanks
      1
      Thanked 1 Time in 1 Post
      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

    4. The Following User Says Thank You to EdNerd For This Useful Post:

      FlaAveo5 (05-15-2018)

    5. #4
      Almost time to do my timing belt
      Join Date
      Aug 2012
      Location
      Northeast
      Posts
      1,231
      Thanks
      3
      Thanked 89 Times in 81 Posts
      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.

    6. #5
      What do you mean there's no turbo? FlaAveo5's Avatar
      Join Date
      Sep 2011
      Location
      Fort Lauderdale,Fla.
      Posts
      296
      Thanks
      64
      Thanked 10 Times in 10 Posts
      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.

    7. #6
      Should I keep it? EdNerd's Avatar
      Join Date
      Feb 2016
      Location
      SW AZ
      Posts
      52
      Thanks
      1
      Thanked 1 Time in 1 Post
      I thought you were replying to this thread:
      Thinking about getting a transmision flush done

      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





    Similar Threads

    1. Replies: 8
      Last Post: 02-19-2016, 07:10 AM
    2. Manual Transmission Fluid Flush?
      By wolfforlunch in forum Engine & Drivetrain
      Replies: 6
      Last Post: 12-11-2015, 02:35 PM
    3. Automatic transmission fluid flush
      By psmedley in forum How-To
      Replies: 20
      Last Post: 04-10-2015, 08:08 PM
    4. transmission fluid
      By red04fourdoor in forum General Discussion
      Replies: 22
      Last Post: 10-11-2014, 01:52 AM
    5. Replies: 4
      Last Post: 07-08-2014, 05:30 AM

    Posting Permissions

    • You may not post new threads
    • You may not post replies
    • You may not post attachments
    • You may not edit your posts
    •