2007 - 2014 GMC 6.2L engine and 6L80E 6spd trans - random surging while accelerating at speeds under 45

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testdepth

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Looking for anyone else out there using this engine and transmission having similar problems. 170000 miles on mine. I have searched the internet and cannot find anything. This problem throws no codes or check engine and is random. For instance mine went 9 days without a problem and then one morning it surged and stalled. The next day it surged but didn't stall and the last two days nothing as it drove fine. Does not happen after the engine is at normal temp of 210F. I can't be the only lucky person.
 

Joseph Garcia

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Can you describe your issue in greater detail? Does this surge seem like a temporary 'disconnect' between the motor and the transmission (like the torque converter issue)? The torque converter is a known weak spot on these GMT900 trucks, and at your mileage, that is actually a lot of miles for the torque converter.

You may want to have a transmission shop look at it, because you don't want the torque converter to fully grenade and take out your transmission with metal particles.
 
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testdepth

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The problem happened to my wife again today while driving at low speed from a dead stop. She drove from my house about 2 to 3 miles and stopped at a stop sign. She made a left turn and proceeded to accelerate when this Denali started to surge and RPMs running up and down like it was not getting fuel and going to die. It did not die. She pulled to the side of the road and shifted it to park and then back to drive and it drove the rest of the day just fine. This problem is very random and sometimes goes weeks without any problem. Out of the blue it does this. Always at low speed and always this same scenario. Left turn, accelerate, surge, either dies or regains speed and never happens again that day. I honestly hope it fails hard. Nobody has been able to tell me why this is happening?? No codes or check engine light.
 

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