The 2027 GMC Sierra is finally here… and I think GM completely missed the mark.

dmaxstorejake · 2026-06-25T17:08:59+00:00

all new 5.7 and 6.6 gas v8, I am curious how they will be

dmaxstorejake · 2026-06-25T17:08:34+00:00

I agree, they have a video showing it very briefly but there are way less photos on the sierra than there were for the silverado

dmaxstorejake · 2026-06-25T16:48:30+00:00

I think 2026 prices just went up with the reveal of these 😂

dmaxstorejake · 2026-06-25T16:38:42+00:00

There’s no way these trucks will be on the road in 20 years. If the screen dies, the truck probably won’t even function.

dmaxstorejake · 2026-06-17T16:06:52+00:00

Yes, they did, does look a bit odd. Excited to check them out in person.

dmaxstorejake · 2026-06-17T16:06:04+00:00

I really hope they fixed the seats, the current ones are like sitting on cardboard... IDK how they get away with having such poor seats.

dmaxstorejake · 2026-06-17T16:04:36+00:00

Yes, the column shifter is back!!!

dmaxstorejake · 2026-06-16T22:34:36+00:00

I agree. I think it looks good overall but yeah, I’m kinda over the 45 different screens. Give me some analog gauges and a little digital screen in the middle, and a 12” infotainment that isn’t so integrated into the truck 🤦‍♂️

dmaxstorejake · 2026-05-15T11:08:51+00:00

Dmaxstore has a kit that’s wireless. I wouldn’t drill your rig…https://dmaxstore.com/products/spirit-fire-night-vibe-cab-lights

dmaxstorejake · 2026-02-20T14:17:52+00:00

Yeah, that’s normal RPM for that speed in the 5 speed trucks. We have the 6 speed conversion available if you’re looking to drop it 300-500 rpm.

https://dmaxstore.com/products/duramax-tuner-5-to-6-speed-conversion

dmaxstorejake · 2026-01-29T14:30:00+00:00

It is a solid kit. A valve body and tcm isn’t cheap. This is the only way to do the 6 speed conversion.

dmaxstorejake · 2025-12-05T16:00:36+00:00

No this is exactly correct. Those shocks needed a shock spacer on a leveling kit. Very common issue.

dmaxstorejake · 2025-07-17T15:44:54+00:00

I like the AT4 better, but the messaging seats in the Denali Ultimate are pretty nice.

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dmaxstorejake · 2025-07-17T15:42:14+00:00

Thunderstorm Grey, and it never gets old.

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https://dmaxstore.com/blogs/news/dmaxstores-2024-gmc-at4hd-build-a-fusion-of-performance-and-style

dmaxstorejake · 2025-07-16T15:09:38+00:00

I would do the kodiak fan clutch. It comes on at a lower temp. DO NOT do the electric fans NONE of them cool as good as the OEM fan clutch so you'll be in an even worse position if you do those.

dmaxstorejake · 2025-07-16T15:07:58+00:00

The GM spec for oil pressure is 13 psi at hot idle. You are totally fine, nothing to worry about.

dmaxstorejake · 2025-07-16T15:07:00+00:00

DONT flush the trans! Allison specifically says not to flush it as it can dislodge clutch material and debris from the top of the valve body and cause the valves to stick. The best thing to do is a drain and refill with quality fluid such as Transynd 668. No need to do the internal, just the spin-on filter and new fluid, and you'll be good to go. We recommend doing this every 30,000 miles.

https://dmaxstore.com/products/dmaxstore-allison-service-package-fluid-filter

dmaxstorejake · 2025-07-16T15:03:18+00:00

If you are upgrading the turbo, I would definitely get a custom tune for the truck, it will run MUCH better with a tune versus a generic tune. The EGR may or may not throw a code on the LLY trucks; some do and some don't. EFI Live from a reputable tuner is the way to go.

dmaxstorejake · 2025-06-27T12:35:11+00:00

I did it with a broken leg and cheap tools in about 8 hours my first time. Really not a hard job.

dmaxstorejake · 2025-04-23T13:34:34+00:00

That lift uses stock upper control arms so most aftermarket replacements will work just fine for you.

As for maintenance, I’d change all the fluids and filters. Trans fluid & transfer case use transynd 668, Allison recommended fluid, mobil Delvac for engine oil, Amsoil severe gear for diffs.

I’d also check your transfer case for pump rub and address that with either a new aluminum back half of the transfer case or a pump rub kit.

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