Don't Do What I Did- Tranny Flush on '17 Tahoe

Discussion in 'Engine & Drivetrain' started by dmad1, May 1, 2019.

  1. dmad1

    dmad1 Member

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    On my '12 Tahoe LT I changed the fluid and it was a piece of cake. Just remove the clip that holds the return line from the top right corner of the radiator, insert a piece of 3/8" tubing and place the end into a catch bucket. I marked the bucket at each gallon level so I could see about how much I was pumping out. Had the wife help by starting and running through the gears for about 3 seconds each. Stoppedd at a gallon and added a gallon and repeated until I had a strong pink fluid coming out. Didn't take long at all. Now advance to this past Sat. as I changed or tried to change the fluid in my '17.

    As before, removed the clip and inserted the tubing. Only this time it took 1/2" instead of 3/8". Seemed a little different from before but just thought GM wanted a little larger line. Wife was not available so since it went so well the last time, decided I could start it and run it through the gears. I did that and let it run a few minutes to pump it out and then went back around to check on it. The tubing had been blown out of the radiator and fluid was everywhere and a huge puddle one the driveway. And the engine began to have a big knock and rattle. The fluid looked very nasty and I thought I must have burn the tranny big time for it to look like that. It had quit pumping and only had about a quart in the bucket. Tried the procedure again a couple of time and still not pumping and then noticed there was no oil pressure and the warning message to shut off the engine. Yep, I had pumped 7 qts of engine oil out and it was knocking bad. After retracing everything, it dawned on me that GM had moved the tranny return line lower down the radiater and run the engine oil into the top of the radiator where the tranny fluid used to return from. I refilled the oil pan and it has quietened down somewhat but am very concerned what damage I may have done to the rod and main bearings. I did drive it around the neighborhood with no noticeable issues. Looking for suggestions whether I should plan on continuing driving it on my 90 mile round trip everyday or get rid of it. Needless to say I am upside down on the lien... Ideas appreciated.
     
  2. Coronado126

    Coronado126 TYF Newbie

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    If it was me, I would sample the engine oil that you have in there now along with some additional sampling done often until you feel more comfortable, plus sample any of the old oil if you have it still and see what the reports say.

    If it says excessive material, I'd trade it off ASAP. Otherwise I'd truck on.
     
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  3. FrankU

    FrankU Full Access Member

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    How long did it run with the line disconnected ? How long did you hear the rattle for ?
     
  4. dmad1

    dmad1 Member

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    I think I started it 4 times trying to get it to pump fluid. Knocked each time showing no oil pressure. Probably 4 minutes total run time. I added new oil when I realized what I had done and changed the filter. Ran it for about 30 miles showing good oil pressure and changed the filter again. Caught some of the oil that drained out as I was removing the filter. Can see small flakes. Have changed the oil and filter again and have run it about 60 more miles. Just checked the dip stick and can see a few flakes and some small splinter like pieces. Thinking maybe I need to change the filter again and see that will clear the oil up some. I get a little "braaaap" when I start in after sitting over night. Just for a couple of seconds if that long. Will not do it again until it sits overnight again. The oil pressure runs close to 40 steady and after it is warm, it idles about about 22. No noises while idling or running but the small fragments on the dip stick leaves me with big concerns. Just wondering what kind of clearance tolerances are allowable without doing major damage? Just can't really afford to trade it right now, but would hate for my wife to break down as she makes two 45 mile trips daily. Any ideas appreciated. If it shells, I will loose what equity I have as a trade in. It had 43K on it. :(
     
    Last edited: May 15, 2019
  5. iamdub

    iamdub Hold on... Lemme overthink this for a bit...

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    After some satisfactory oil changes (seeing no particulates, etc.), I'd treat it like a high-mileage engine and run heavier oil. Something like 15w-40. I doubt it'd break down without any warning and even then, it'd probably just start knocking but not seize and leave anyone stranded. 45 miles isn't all that far away. Get AAA.
     
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  6. SnowDrifter

    SnowDrifter Full Access Member

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    Sorry to hear OP


    It's not my intent to sound rude here, but this is yet another reason why I recommend against pulling off the cooler line to get trans fluid out. Drop the pan(which you should be doing every 30-50k anyway), vaccuum it through the dipstick tube, or install a pan w/ a drain plug. Trying to pull off the cooler line and do it that way is just fraught with risks.
     
  7. Mickey_7106

    Mickey_7106 Full Access Member

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    It's a '17. If the engine goes, won't it be covered under warranty?
     
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  8. live2pull

    live2pull Member

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    I second this. If you just cannot get the engine to recover, you may just have to bend over either on the trade in or purchasing a crate motor.

    If the dealer can sufficiently prove that the engine was damaged do to "negligence", I dont think they would honor the warranty. However, you might get lucky and they may replace it under warranty. 50/50 I'd say.
     
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  9. iamdub

    iamdub Hold on... Lemme overthink this for a bit...

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    LOL @ GM's "warranty". Aside from the fact that this is an unwarrantable issue caused by the OP, HE would have to prove that he IS NOT the cause for the failure, not GM proving that he IS. It'd be too easy for the dealership to find evidence that the system was tampered with. I'm quite sure there are at least witness marks on the oil line fittings. Maybe there's a datalog deep in the PCM that only they can access that would show the oil level sensor reporting "full" then "low" then the engine being started and ran while the sensor was reporting "low" and the oil pressure sensor reporting "zero". Who knows what they can dig up. If he tried to claim it under a warranty, they'd find evidence and deny and record it. If he decides to sell or trade it, what they found would be a bad stain on the vehicle's history.
     
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  10. Mickey_7106

    Mickey_7106 Full Access Member

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    i think you're giving them way too much credit for what you think they can figure out. Plus why would it be up to the OP to prove he didn't mess up? he doesn't have to say anything other than "there's something wrong with my vehicle"...

     

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