14 LTZ Shutter/shake/ vibration under light throttle

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TaboltB2015

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If the GM dealer did the work, take it back and explain the issues to them. A slight metal rattle could be something as minor as a loose heat shield that they bumped or did not reconnect after the TC repair. Vibration, could that be your AFM kicking in and off and its more pronounced now with the new TC? Random shake on the highway at 70-75 could just be tire balancing. A weight or two could have come off while they were doing some work, etc. as well.
Yes local GM dealer did the work I was recommended to them from co worker that has all his stuff done by them. Tires were put on about 9k ago, I’ve thought maybe it’s because they are 22” but would think if there was a issue I would feel it all the time not just on light acceleration, I will watch the dash on the V4 to V8 to see if that’s when I feel the vibration
 
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TaboltB2015

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I will try to get a video of it later when I get home from work
I got under it and was touching anything they would have taken off and the rear clamp on the exhaust was put on but was not tightened down.. first picture is before I tightened it 2nd is after lol simple clamp, feel like they would have doubled checked before they put it back down on the ground. I drove it and no noise
 

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TaboltB2015

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If the GM dealer did the work, take it back and explain the issues to them. A slight metal rattle could be something as minor as a loose heat shield that they bumped or did not reconnect after the TC repair. Vibration, could that be your AFM kicking in and off and its more pronounced now with the new TC? Random shake on the highway at 70-75 could just be tire balancing. A weight or two could have come off while they were doing some work, etc. as well.
I watched the dash from where it goes from V4 to V8, most definitely feel the vibration in V4 with holding light throttle it’ll stay in V4, anything more than that it’ll obviously go to V8 but the vibration stays can definitely feel it “kick” back into V8. What a goose chase
 

j91z28d1

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might be a good idea to get the 4 cyl mode turned off as soon as you can. I doesn't keep it from eating lifters but as far as I've seen, it doesn't hurt and you'll need it turned off anyways when you go full delete
 

jdwood1111

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I watched the dash from where it goes from V4 to V8, most definitely feel the vibration in V4 with holding light throttle it’ll stay in V4, anything more than that it’ll obviously go to V8 but the vibration stays can definitely feel it “kick” back into V8. What a goose chase
Yep, sounds like the afm system is what you are feeling. Couple options:

range device will plug in to your obd2 port and keep that from occuring but need to be taken out to pass inspections. It’s around $240 on Amazon.

There is a place/guy you can send your pcm to I believe that will turn it off for around $50 if I can find the link I’ll post it up.

Find a local person that can tune it out with HP Tuners or similar. My guy would turn it off for $200 but did a full tune for $600.

I went with the range device to start that worked and then had a custom tune done which included afm turn off.

Glad the metal noise is sorted out. But check that exhaust, is that a pin hole I see?
 
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TaboltB2015

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Yep, sounds like the afm system is what you are feeling. Couple options:

range device will plug in to your obd2 port and keep that from occuring but need to be taken out to pass inspections. It’s around $240 on Amazon.

There is a place/guy you can send your pcm to I believe that will turn it off for around $50 if I can find the link I’ll post it up.

Find a local person that can tune it out with HP Tuners or similar. My guy would turn it off for $200 but did a full tune for $600.

I went with the range device to start that worked and then had a custom tune done which included afm turn off.

Glad the metal noise is sorted out. But check that exhaust, is that a pin hole I see?
I started to look up just a simple plug in one, found the range one as well, luckily I don’t have inspections here in Kansas so don’t have that problem, I’d really would like to have it deleted all together but the shop that I see that does it and looks like they do great work is pricey at about 5k for a complete rebuild, tune, ect. On the exhaust I think that is just dirt built up, taking about that dark spot just after the cat?
 
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TaboltB2015

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Little update for ya, the Tahoe was in shop for for the last two weeks, turns out they didn’t pull the pan on transmission after all they put a reman converter in and did drain and refill, put it back together… I went back over the last two weeks to go on test drive to get it to vibrate “they couldn’t get it to do it” “” had computer plugged in to turn the solenoids on and off for torque converter clutch did not improve with off or on got it to act up and was able to get it to make a drone noise, they opened a case with GM about this, they say not transmission more in transfer case or drive shaft, fast forward to yesterday went on another test drive this time with the little magnet ear deal that picks up vibration did all that. Today I picked it up so I can do my weekend chores and here is a few videos of what I can get the drive shaft to do. I have it in neutral and can get it to clunk back and forth seems more in the yoke areas? Well for some reason I can’t get the videos to load here.
 
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TaboltB2015

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Little update for ya, the Tahoe was in shop for for the last two weeks, turns out they didn’t pull the pan on transmission after all they put a reman converter in and did drain and refill, put it back together… I went back over the last two weeks to go on test drive to get it to vibrate “they couldn’t get it to do it” “” had computer plugged in to turn the solenoids on and off for torque converter clutch did not improve with off or on got it to act up and was able to get it to make a drone noise, they opened a case with GM about this, they say not transmission more in transfer case or drive shaft, fast forward to yesterday went on another test drive this time with the little magnet ear deal that picks up vibration did all that. Today I picked it up so I can do my weekend chores and here is a few videos of what I can get the drive shaft to do. I have it in neutral and can get it to clunk back and forth seems more in the yoke areas? Well for some reason I can’t get the videos to load here.

Ok here is a google link for two different videos, also was about to hear the drivers rear brakes touching which ain’t normal, was told don’t see anything wrong with them


 

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