New trans issues

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Metalcd

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Oct 19, 2025
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Hello, I have concerns about my transmission. I completed the install on November 7th including the garage shift procedure. That afternoon I took it for a 5 mile test drive and noticed that it was a delay and hard shift into 5th gear while under load. This past Friday the 14th I started hearing an intermittent grinding noise while I was driving. Today, Sunday the 16th, I noticed it is present from idle to about 1100rpm, then absent until about 1600rpm then present again. Still have hard shift into 5th gear. And while I was on my way home going down the highway, I noticed that while it should have been in 6th gear and around 1600-1800 rpm, my truck was running around 2000rpm at 65mph as if it was not going into 6th gear. I exited the highway then re-entered only to find out that it was no longer shifter smoothly even though 4th gear automatically nor manually into 5th or 6th gear’s. When I got off at the next exit and made my way home, it was delaying shifting into 2nd and 3rd gears and would not go beyond 3rd gear in drive or manual modes. When I got home I can smell a burning smell.

This is what I sent the supplier. They shipped it with the TECHM programmed according to my vin. I have a 2 year warranty with this transmission. I really don’t want to swap it out again.

Any advice is appreciated.
 

Joseph Garcia

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It would be good to know what you are driving, so that we can help you assess your issue. All that we know now is that you are having an issue with a recently replaced 6 speed transmission. Please post these missing details.

@NickTransmissions is our resident transmission expert, and he will chime in with his thoughts and perspectives.
 
OP
OP
M

Metalcd

TYF Newbie
Joined
Oct 19, 2025
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It would be good to know what you are driving, so that we can help you assess your issue. All that we know now is that you are having an issue with a recently replaced 6 speed transmission. Please post these missing details.

@NickTransmissions is our resident transmission expert, and he will chime in with his thoughts and perspectives.
Sorry about that. I have an 08 Yukon xl Denali with over 296000 miles on it.
 

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