I bough a New Truck Chevy 2500 Diesel

up2665

OP

July 15, 2026 at 5:13 PM ET

#1

I bought a new truck, GM 2500 Duramax Diesel 2026 Model High Country. I also bought a new transmission and torque converter from Nex Gen at the same time. I had it delivered to a Chevy Dealership. The transmission was installed on a brand new vehicle. The 500 mile break in was followed to a "T", all of it including the 500 mile breakin. FYI I never depressed the accelerator more than 1/4 of the way but other than taking off slow it doesn't (won't) have an impact. BTW > > > when you rev up the engine it will change gears. I relearn the transmission when installed.

The Chevy Dealership called NexGen on the phone when installing it.''

I think it may be slipping. When I require more power the transmission downshifts. It is rough!

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up2665

July 15, 2026 at 5:23 PM ET

#2

The truck has the 10L1000 transmission in it. It feels like I'm hit or hitting something else when it shifts but I'm not hitting anything and no one is hitting me. It is a kick in the pants for sure!! It happens when the transmission fluid is above 130 degrees. Not 190 . . .

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up2665

July 15, 2026 at 5:45 PM ET

#3

I'm towing (a bumper pull) 3,500 lbs with it. I just went across the country with it It has 11,000+ miles on it, just under 12,000. I texted Next Gen the guy there asked me "what my order number was". I'm retired now.

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TheCarGuy

July 17, 2026 at 1:59 AM ET

#4

Were you able to provide your order number to NextGen? When did you buy the truck and have it installed, and when did you notice transmission issues?

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up2665

July 17, 2026 at 7:47 AM ET

#5

TheCarGuy wrote:

Were you able to provide your order number to NextGen? When did you buy the truck and have it installed, and when did you notice transmission issues?

No, I wasn't. I bought the truck from Champlain Chevy in Enosburg, VT. They also installed the new transmission.

I noticed transmissions issues at 4K'ish miles .

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