2024 GMC 2500 AT4 Gas

Doodle · May 27, 2023

On 5/19/2023 at 10:01 PM, the8rotor said:

@Doodle beautiful truck! I have the same fan-like noise behind the dash. I've noticed only when the ac is on. I had it in my 21 GMC as well?

Also, have you noticed the allison transmission has a little whine to it? Lmk what the dealer says on your fan noise. I just turned 1k miles on the odometer so I'm changing the oil this weekend and towing next weekend.

I do definitely notice some “whine” with the the new Allison. Nothing annoying, but it’s there. I finally got the pickup to the dealer today to diagnose that “noise”. The tech could hear what talking about, although faint, and went to his computer to check any TSB’s. About five minutes later came back with a document that pretty much to a tee summed up what I was experiencing. It was PIT5544G for those that want the specifics.

Some customers may comment on a hydraulic rush or flow type noise from the power steering gear. The noise is most noticeable in the cab at idle, with all accessories off.

It only affects vehicles with RPO code NV8. Basically it’s noise from the Active Hydraulic Assist Power Steering system. So GM considers this “normal”. So I don’t really care to hear it but it is what it is I guess. You only hear it in park or idling with the radio and HVAC off so I guess it’s not a huge deal. This L8T is so quiet I imagine on the diesel you’d never even hear it. But so far thats the only issue I’ve had and thats pretty minor in the scheme of things. Really loving this new platform.

the8rotor · May 27, 2023

1 hour ago, Doodle said:

I do definitely notice some “whine” with the the new Allison. Nothing annoying, but it’s there. I finally got the pickup to the dealer today to diagnose that “noise”. The tech could hear what talking about, although faint, and went to his computer to check any TSB’s. About five minutes later came back with a document that pretty much to a tee summed up what I was experiencing. It was PIT5544G for those that want the specifics.

Some customers may comment on a hydraulic rush or flow type noise from the power steering gear. The noise is most noticeable in the cab at idle, with all accessories off.

It only affects vehicles with RPO code NV8. Basically it’s noise from the Active Hydraulic Assist Power Steering system. So GM considers this “normal”. So I don’t really care to hear it but it is what it is I guess. You only hear it in park or idling with the radio and HVAC off so I guess it’s not a huge deal. This L8T is so quiet I imagine on the diesel you’d never even hear it. But so far thats the only issue I’ve had and thats pretty minor in the scheme of things. Really loving this new platform.

Appreciate the info on the noise! One of those things I guess we just have to put up with. Doesn't help they made these trucks sooooo quiet

Dunn · June 4, 2023

On 5/26/2023 at 7:58 PM, Doodle said:

I do definitely notice some “whine” with the the new Allison. Nothing annoying, but it’s there. I finally got the pickup to the dealer today to diagnose that “noise”. The tech could hear what talking about, although faint, and went to his computer to check any TSB’s. About five minutes later came back with a document that pretty much to a tee summed up what I was experiencing. It was PIT5544G for those that want the specifics.

Some customers may comment on a hydraulic rush or flow type noise from the power steering gear. The noise is most noticeable in the cab at idle, with all accessories off.

It only affects vehicles with RPO code NV8. Basically it’s noise from the Active Hydraulic Assist Power Steering system. So GM considers this “normal”. So I don’t really care to hear it but it is what it is I guess. You only hear it in park or idling with the radio and HVAC off so I guess it’s not a huge deal. This L8T is so quiet I imagine on the diesel you’d never even hear it. But so far thats the only issue I’ve had and thats pretty minor in the scheme of things. Really loving this new platform.

Had a 2020, 2022 and now 2023 and they all had that noise......I figured it was normal and from power steering as nothing felt weird but all my trucks had and have that noise....

BuckWallace · July 11, 2023

On 5/26/2023 at 7:58 PM, Doodle said:

I do definitely notice some “whine” with the the new Allison. Nothing annoying, but it’s there. I finally got the pickup to the dealer today to diagnose that “noise”. The tech could hear what talking about, although faint, and went to his computer to check any TSB’s. About five minutes later came back with a document that pretty much to a tee summed up what I was experiencing. It was PIT5544G for those that want the specifics.

Some customers may comment on a hydraulic rush or flow type noise from the power steering gear. The noise is most noticeable in the cab at idle, with all accessories off.

It only affects vehicles with RPO code NV8. Basically it’s noise from the Active Hydraulic Assist Power Steering system. So GM considers this “normal”. So I don’t really care to hear it but it is what it is I guess. You only hear it in park or idling with the radio and HVAC off so I guess it’s not a huge deal. This L8T is so quiet I imagine on the diesel you’d never even hear it. But so far thats the only issue I’ve had and thats pretty minor in the scheme of things. Really loving this new platform.

Nice truck! I have the exact same truck and noticed the exact same noise you're describing at idle. I also came up with the same conclusion regarding the hydraulic steering. With the windows down or radio on I don't really hear it, but it's definitely an annoyance. I'm coming from two Tundras before this truck and have noticed GM says a lot of things are "normal" that I'm not used to with Toyotas .

Doodle · July 12, 2023

Just got back from a 900 mile roundtrip (unloaded) with the new GMC. Running anywhere from 69-80 depending upon which highway I was running on. Averaged about 15.2 mpg which I was pretty happy with overall. Still at less than 2500 miles so might get better in time. I think if I ran 65 this thing would get 17-18 pretty easy. Amazing for a pickup that weighs in at about 7500 lbs and is way in the air with 20" wheels. I was really impressed with how well the transmission keeps the 6.6 in the powerband. It cruises effortlessly on the interstate and I can pass with ease with just a blip of the throttle. The 6 speed had no issues either, but you can tell this transmission is just more refined and in tune with what the engine is doing. The more I drive this thing the more impressed I am with it. I think if GM ever came out with something like a 7.0L gas with 450-475 hp and 500 tq with this 10 speed, there really wouldn't be a big reason to get a diesel unless you were towing heavy all the time. The 6.6 gas is great but I just think they would grab a big chunk of market share if they had something with just a touch more power. But then I'd probably just say "I wish they made 500 hp" so it probably wouldn't matter, lol.

vucelick · July 12, 2023

Is that hand calculated mileage or according to the truck computer?

UWSkier · July 13, 2023

20 hours ago, Doodle said:

Just got back from a 900 mile roundtrip (unloaded) with the new GMC. Running anywhere from 69-80 depending upon which highway I was running on. Averaged about 15.2 mpg which I was pretty happy with overall. Still at less than 2500 miles so might get better in time. I think if I ran 65 this thing would get 17-18 pretty easy. Amazing for a pickup that weighs in at about 7500 lbs and is way in the air with 20" wheels. I was really impressed with how well the transmission keeps the 6.6 in the powerband. It cruises effortlessly on the interstate and I can pass with ease with just a blip of the throttle. The 6 speed had no issues either, but you can tell this transmission is just more refined and in tune with what the engine is doing. The more I drive this thing the more impressed I am with it. I think if GM ever came out with something like a 7.0L gas with 450-475 hp and 500 tq with this 10 speed, there really wouldn't be a big reason to get a diesel unless you were towing heavy all the time. The 6.6 gas is great but I just think they would grab a big chunk of market share if they had something with just a touch more power. But then I'd probably just say "I wish they made 500 hp" so it probably wouldn't matter, lol.

I'm about 700 miles into a 4000 mile tow with my new gasser, and I agree. This thing could use more power. I'm towing about 8000 lb travel trailer and doing about 70 MPH. It downshifts far more than I expected it would to maintain speed. Not revving like my old 5.3L did with the same load, but there have been several times I didn't expect it to need to make 4000+ RPM and it did. Seems the Allison in this truck likes to down shift one more gear than is necessary when it senses a load. I'm hoping it just needs to learn a bit. Plus, the truck only has about 1200 miles on it so hoping things continue to loosen up.

Surprising mileage though. Getting about 8.2MPG. That's climbing up over the Mogollon Rim in AZ, through NM, into TX and OK with some wicked crosswinds.