Suburbans: GMT800 2500 vs. GMT900 2500 vs. GMT900 "Fancy" (Denali/Escalade)

Best "Do Everything" Suburban

  • GMT800 (2000-2006) 2500 with the 6.0L (12C/16H, estimated)

    Votes: 9 52.9%
  • GMT800 (2000-2006) 2500 with the 8.1L (11C/15H, estimated)

    Votes: 8 47.1%
  • GMT900 (2007-2013) 2500, only came with the 6.0L (10C/16H)

    Votes: 0 0.0%
  • GMT900 (2007-2014) Denali XL or Escalade ESV with the 6.2L (13C/18H)

    Votes: 0 0.0%

  • Total voters
    17

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CTX-SLPR

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I tow once or twice a year at most and other than dragging that CL600 home it’s largely been lighter stuff. I’d put the power of the 8.1L for towing vs. the 6.0 on a slightly lower level than those that pull a camper or car hauler more regularly. Sounds nice to have the “last of the Big Blocks” though…
 

Erik the Awful

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My race team captain traded away his GMT800 for a GMT900 a few years back. The 900 interior is definitely a bit classier, but he's already had the transmission rebuilt once. We used both Suburbans to tow the race car but neither was really up to the task. They were both 5.3s with light-duty transmissions, and fuel economy with the 5.3 isn't bad.
 

OutlawDrifter

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Having owned a fully loaded 1/2t GMT900 'burb...I would steer you away at this point from that generation. The 6 speed hunts (they come with 3.08 gears), mind you, mine was tuned and had the exhaust opened up...fully loaded with kids, gear, and dog, it would only do about 14.4mpg @ interstate speeds. That's real world hand calculated numbers. I will NEVER own another 1/2t Suburban (GMT400-present, solid axle rigs are different). I did own a 2500HD CCSB pickup with the 6.0L/6L90E, and it towed everything I ever wanted, but I still didn't love the interior. I think it eeked out a 15.1mpg trip one time at 68mph with a tail wind. The 6.0's need RPM to do the work, they don't have the low end grunt most are used to with SBC/BBC platforms. So be prepared to tach them out when you need to get to the useable power.

I voted GMT800 with the 8.1. A local mechanic had one that was tuned, and other than the stated oil consumption, it got similar mileage to my K2500 454 rig...with more power.

After the GMT400 rigs, the second and 3rd row room was squeezed down a bit...I would ride in the 2nd row of mine, but not the 3rd. For a vehicle that is not used everyday, and needs to be a Swiss Army Knife Jack of all Trades....go with the big block K2500 rig. Be picky, and find the cleanest, lowest mileage one you can for the money.
 

stutaeng

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I think it has to do with gearing on the 6 speeds. The 4L60e 1500 suburbans were typically equipped with 3.73s.

I don't know much on the 1500 GMT 800 suburbans, but the same generation of trucks got as low as 3.08s. I know the 6 speed has a much steeper 1st gear, but 5th & 6th aren't that far off the older 4 speed OD ratio on highway driving.

Even with 3.42 and a 6 speed, the cruising RPM is a tad low for any gas engine in mid- and heavy weight vehicles.
 

Dariusz Salomon

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When I was looking for a truck, I could not test drive anything, as I'm in UK-so my search was theoretical-based on what I read-and also limited to what was available in Europe at this time. My conclusion was, that I can live with 5.7 and 6.0, but not 5.3-too much was against it-the issues too"failure prone by design"rather than quality. I knew it's gonna be at the back of my mind constantly-and saying that I settled for 4l60e(which IS at the back of my mind constantly) but at least engine isn't(too much lol).
 

618 Syndicate

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When I was looking for a truck, I could not test drive anything, as I'm in UK-so my search was theoretical-based on what I read-and also limited to what was available in Europe at this time. My conclusion was, that I can live with 5.7 and 6.0, but not 5.3-too much was against it-the issues too"failure prone by design"rather than quality. I knew it's gonna be at the back of my mind constantly-and saying that I settled for 4l60e(which IS at the back of my mind constantly) but at least engine isn't(too much lol).
The non-DOD 5.3's are as problem free as any other motor. The DOD is the design flaw not the motor itself.
 

someotherguy

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I think it was excesive oil consumption that put me off if I remember. That was a while ago.
That's the issue related to the DOD (displacement on demand, or GM calls it, AFM, active fuel management)

Some of the 5.3's are known for porous head castings, too. Which ones, dunno, one concerned would need to research it (Castech is the keyword to look for)

On the 8.1's I am fairly sure the oil consumption issue is the vent in the bottom of the intake which may serve as the PCV. Later years got a revision in the shape of it. This subject comes up from time to time and having not laid hands on one yet the particulars of it don't stick in my memory, but I do feel pretty strongly that is the root of the issue and totally fixable without major work.

Richard
 

Dariusz Salomon

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That's the issue related to the DOD (displacement on demand, or GM calls it, AFM, active fuel management)

Some of the 5.3's are known for porous head castings, too. Which ones, dunno, one concerned would need to research it (Castech is the keyword to look for)

On the 8.1's I am fairly sure the oil consumption issue is the vent in the bottom of the intake which may serve as the PCV. Later years got a revision in the shape of it. This subject comes up from time to time and having not laid hands on one yet the particulars of it don't stick in my memory, but I do feel pretty strongly that is the root of the issue and totally fixable without major work.

Richard
Yeah-Castech cracking heads-also fuel pressure regulator and intake gaskets-but that's 350s issue too.
 
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