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2019 GMC Sierra AT4 6.2L Transmission Whine and Aggressive Downshift

SDAT4
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SDAT4 New Member

SDAT4

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Just this morning when driving to work I noticed a whining sound then a few miles later when getting off the freeway it started having aggressive downshifts. Upshifting seemed okay but even when I manually downshifted it would jerk hard. I'm at 93k miles so of course out of warranty.

 

Researching the forums, it looks like it could be a number of things including but not limited to: torque converter, valve body, idler gear bearing and torque converter.

 

At 82k my truck developed the "rumble strip" vibration at highway speeds. I flushed the fluid and swapped a new filter myself which did fix that issue. I just don't think fluid/filter will fix this one.

 

This is my daily driver that I also use to tow my toy hauler sometimes on the weekends (which it does great with). I really do not want to have my truck sitting for weeks or months diagnosing and waiting on parts like I've read on other posts.

 

I'm thinking of finding a reputable shop here in San Diego north county area that has experience with the 10L80 or swapping a whole used transmission. I see them for around 2-3k on Car Part/junkyards. 

 

Thoughts?

Bikerjon Enthusiast

Bikerjon

Posted
Posted
6 hours ago, SDAT4 said:

Just this morning when driving to work I noticed a whining sound then a few miles later when getting off the freeway it started having aggressive downshifts. Upshifting seemed okay but even when I manually downshifted it would jerk hard. I'm at 93k miles so of course out of warranty.

 

Researching the forums, it looks like it could be a number of things including but not limited to: torque converter, valve body, idler gear bearing and torque converter.

 

At 82k my truck developed the "rumble strip" vibration at highway speeds. I flushed the fluid and swapped a new filter myself which did fix that issue. I just don't think fluid/filter will fix this one.

 

This is my daily driver that I also use to tow my toy hauler sometimes on the weekends (which it does great with). I really do not want to have my truck sitting for weeks or months diagnosing and waiting on parts like I've read on other posts.

 

I'm thinking of finding a reputable shop here in San Diego north county area that has experience with the 10L80 or swapping a whole used transmission. I see them for around 2-3k on Car Part/junkyards. 

 

Thoughts?

No way would i put a used transmission into my truck especially a used 10L80. Lots and lots of weak points/defects in this trans. Front pump, valve body, torque converter and other weak points. Most tranny shops do not just repair this trans. Complete overhaul or nothing. As far as the valve body you will probably be stuck waiting for months just like everyone else on this forum.

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