Transmission fluid change /flush at 106k

Discussion in 'Maintenance & Upkeep' started by mvoss2576, Nov 19, 2010.

  1. mvoss2576

    mvoss2576 Rockstar

    I'm sure this has been asked.. but I couldn't find it real quick... so I'll ask.

    My 2007 Chevy Silverado classic 4x4 has 106k miles... I need to do some maintenance on it, with the transmisison being my main focus...
    I've heard of the flushing machines...but highly expensive... whats the difference between that and just dropping the pan? Is there a way I can do the flush myself if that's the preferred method?

    I'm planning a 1600 mile trip around Christmas, pulling a trailer...want to make sure everything is ready to rock!
  2. stephan

    stephan Rockstar 4 Years 5000 Posts

    The beauty of the flushing machines is you get the torque converter flushed too, but if you have been getting the trans serviced at the recommended intervals, you probably don't need the tc flushed. Just make sure you get the trans cooler to drain s t requires disconnecting the lines.
    To do a good job of flushing the converter, you would have to service the trans, fill fluid etc, run it to circulate the new fluid with the old that was in the converter, drain & fill again. Probably not worth the money or the work for a couple quarts.
  3. mvoss2576

    mvoss2576 Rockstar

    So dropping the pan (I haven't gotten under that to see if its got a drain) and changing the fluid and filter should be good?
  4. stephan

    stephan Rockstar 4 Years 5000 Posts

    You'll want to drop the pan & replace the filter too. That's the main reason most manufacturers don't put drain plugs in trans pans. Even if it does have a drain plug, pull the pan & repl the filter. Pulling the pan also gives you a chance to check for debris in the pan & get an idea of how your trans is doing. If there's a lot of it, save it & show it to a trans man. He can tell you what it is & can judge by the quantity just how bad or good your trans is.
    Have you been having regular trans services? What mileage interval?
  5. 2COR517

    2COR517 Epic Member 5+ Years 1000 Posts

    It's easy and safe to flush the fluid in your trans yourself. Start by dropping the pan, and removing the filter. This is a good time to install a drain plug in your pan. You can weld in a pipe threaded bung, or use a bolt together style like this.

    While it's important to change the filter each time like Stephan mentioned, the drain plug will make the whole process easier and cleaner.

    Install the new filter, pan gasket, pan bolts, etc. Overfill the trans, put in two gallons. Now, the fun part. Remove one of the lines at the trans cooler. Using a piece of hose and a large bucket, start the truck. Direct the trans fluid flow into the bucket. Once you have pumped out about a gallon, shut off the truck and add another gallon of fluid. Start the truck back up and keep pumping till you see the color change to the new clean fluid. Shut the truck off and put everything back together. Check the fluid level and adjust as necessary.

    A few things to consider:

    A pan and filter service will typically change about a third of the fluid. Maybe a little more if you let the trans sit overnight and the converter drains back some. This process will change about 90% of the fluid, and do it safely.

    If you can shift the transmission through the gears while pumping out the old fluid, you will pick up a few more percent from the valve body, accumulators, etc.

    You might want to figure out which line to pull first. Most effective is to pull the return line, install a fitting to connect your hose to. This will allow you get the old fluid out of the cooler also. A helper is good, he (or she of course) can add fresh fluid to the trans as it's being pumped out so you don't have to shut down and restart during the process. Or simply sit in the cab to shut down if needed while you do the work.
  6. JIC396

    JIC396 New Member

    Hi Folks,

    New to the site...just got my it.

    My trans service procedure that I have used works like this...

    I have a top sider oil change system that I paid $30 for at Overtons. I draw the fluid out of the top...add 4+ a couple of miles and do it again.

    I'd say you get at least 90% clean fluid. If you have enough clutch/bushing material in the pan to clog that big ol filter then servicing it anyway you decide won't help anyway.

    Do this every 60,000 and you won't ever have to drop the pan or fool with cooler lines.

    Personally I've seen the flush machines introduce someone elses crude into an otherwise clean trans...

    Just my way but it's worked in every vehicle I've owned for 15 years.

  7. 2COR517

    2COR517 Epic Member 5+ Years 1000 Posts

    That procedure won't even come close to getting 90% of the fluid. Sorry, just simple math.
  8. JIC396

    JIC396 New Member

    Ok you are do you do this? Pay somebody to use a flush machine that has been used 1,000 times????
  9. 2COR517

    2COR517 Epic Member 5+ Years 1000 Posts

    Did you read post #5? I've posted the same procedure on other threads here also.
  10. stephan

    stephan Rockstar 4 Years 5000 Posts

    Good point, the machine is only as good as the guy who takes care of it & cleans it out. We used to have a "gas caddy" we would pump fuel out with when we had to drop tanks. We all used it, but no "one person" was responsible for cleaning it, so it NEVER got serviced/cleaned.

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