Still a rookie at TexAgs but trying again - I'll try to be to the point..
We have a 2017 GMC Denali pickup - this truck is in great physical shape but it needs a new engine. It is currently at the mechanic where he took it in as soon as the check engine light came on - when they went to diagnose it they realized the engine is shot (bent rods and more) and the only fix is a new engine. He has taken great care of this truck - regular oil changes, it's clean and the interior has no rips/tears or stains. This would be a great project truck for someone who knows how to replace an engine. Anyone interested - considering selling it since he has the option of a company truck that we didn't chose beforehand since he loves this truck so much
2017 GMC Sierra Denali
White
108k miles
Black leather interior
Tri-fold hard bed cover
One owner, no smoking
No body damage, light touched up paint on the hood

4wd?

2wd

Price? Obviously new motor required, but does it run and make hellacious noise or is it locked up?

It doesn't run, currently at the mechanics awaiting a decision from us, it would need towed. Would take $15,000 for it.

I have some questions aggiepaintrain@gmail.com

Active Fuel Management lifter failure is also a known problem in the 5.3 GM/Chevy engines with AFM. I had a 2012 Silverado with the same issue at 6yrs/~115k miles. Only options to salvage the truck were a whole upper rebuild or new motor.

I'm not positive about the exact series of events that led to the bent rods, but I am 100% confident that this problem started with an AFM lifter failing.

Where is it located?

what does a new motor cost for a vehicle like this? asking out of curiosity.

https://www.ebay.com/itm/374226815886

A junkyard pullout would be in $4k range. You should then spend another $1,000-$1,600 to delete AFM hardware.

Whats the price?

In my case the dealer quoted me $4500 for the rebuild or ~$6500 for a crate motor, albeit this was in 2019.

Thanks for all the replies and interest. We sold it. Leaving the post up in case others are researching what happened to their engine. Like other posts said, this is a problem in these motors which is very frustrating.

I had the same thing happen to my 2015 Sierra, got "lucky" it was only at 85k miles and still under powertrain warranty.

I have the 5.3 and bought the Range DFM disabler. Is that known to be a good solution?

Did the same, I'm at 145k now and haven't had any issues with it

2015 5.3L here with 141k miles, put in Range disabler at 25k miles, better mpg, better throttle response of course and it stopped burning excessive oil.

Ok cool. I put mine on around 55-60K. Fingers crossed I can get 200K without this issue.

Price
Pics
Repair cost?

mm98 said:

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I have the 5.3 and bought the Range DFM disabler. Is that known to be a good solution?

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Been considering this.

They really work?...plug n play?

I would buy one simply for the auto/stop feature to go away.

Worried it'll void my warranty, but they advertise they don't.

About to hit 100k on my 2016 Sierra 5.3.

Probably going to tear up the transmission too as it hard shifts in and out of first.

Supposed to be covered by the "forever warranty" on powertrain that came with it from DeMontrond. Kept up with maintenance so far.

NM

So far so good. Mileage dropped a bit as expected. 8sp actually shifters better with far less jerks.

No complaints so far.

If you have transmission rebuilt or replaced with OE, get a torque converter from Circle D Specialties and ensure your trans cooler / trans cooler lines are cleaned before being connected to new unit.

I'm curious. What does a 8L90 or 10L90 rebuild cost these days?

I had a Circle D disciple rebuild my 4L60e about ten years ago and it was $2400 then with the standard torque converter with an aftermarket Hayden cooler

I have no idea. My recommendation would be to replace with OEM unit if planning to keep the truck. Again with a Circle D converter.

The 4L60e converters aren't problematic like the 6L80e converters have proven to be. I haven't seen many examples or at least causes of 8 speed / 10 speed failures, but suspect the culprit would again be the converters.