The GMT800 series is easy to work on, parts are still plentiful and fairly in expensive. They’re a great rig. At this point in time, with most of the trucks of this generation being anywhere from 23 years old on the 2000s to 17 years old with the 2006, the majority of the trucks you find for sale are going to be high mileage and varying conditions. There are definitely low mileage rigs out there in good condition. But to get one takes some work lol. You will more than likely need to be willing to travel far and wide and to get one. I lucked out in 2015 and my scored a good deal on my 2006 Yukon xl Denali only two hours away from my home town in the mountains. It had 74k on the odometer and was a one owner rig. I’ve since put over a 100k onto it in the 8 1/2 years I’ve owned. I absolutely love it. It’s not perfect. My clearcoat is garbage because GM had garbage clearcoat in that era. But that hasn’t stopped me from running it. The space in the long wheel base XL versus the regular Yukon is unbeatable! I specifically wanted a long wheel base for over all space the rig gives me. My LQ4 6.0 has never let me down. I tow boats up and down mountains pretty regularly now.it pulls all day long without a second thought! The 5.3 is a great engine as
@OR VietVet mentioned above. It’s a tried and true engine that’s just crazy reliable even when they’re beat and not maintained. Personally I felt though that it was not quite enough power for the weight of the XL Yukon being longer and heavier than a Tahoe or regular Yukon, and that was the deciding factor in wanting a Denali trimmed Yukon xl for me since I wanted the 6.0. I drove both a 2004 Yukon xl SLT, and a 2005 Z71 package suburban that had 5.3s and I definitely noticed the 6.0 moves these long wheel bases easier than the 5.3.
I run a mobile auto detailing business with my Denali. And I use it on road trips for vacations. It handles it all. It’s been reliable, stupidly comfortable with big leather bucket seats, it rides nicely on the air assist shocks in the rear end and computer dampened auto ride shocks in the front. Keep in mind you’re probably going to need to address this system if you end up with one. They’re known for needing replacement and most owners just let it ride since the rear shocks still ride ok even when the air bladders blown and the compressor doesn’t fill them up to keep the trucks level. I replaced mine with the top quality aftermarket company that remanufactures the air assist shocks and I’m very happy.
Some things to know about the GMT800 Denali trim Yukon and Yukon XL, and along with the Escalade ESV. First off the best years were 2005 and 2006. These were the last two years of the platform. Most of the bugs in the designs of these trucks were worked out by 2005 and 2006, most notable the change over from one single mechanical clutch driven engine cooling fan up front, to two computer driven fans that eliminated the mechanical clutch. The clutches for the fans were a known failing point and a pain in the behind to replace. I specifically searched for a 2005 or 2006 to avoid the clutch fan issue. And the computer controlled fans give much better filling performance for these rigs and my fans have never had a single issue. That and the fact that the fan setup doesn’t block the front of the engine in where the water pump, all the pulleys and tensioners, and cooling hoses are, makes it crazy simple to replace all that. On the pre-2005 rigs, the fan and shroud needs to be removed to access all that for replacement. It’s not hard to remove but adds a tone of time to the repair jobs, where as every accessory at the front of the engine is easily accessible with the 2006’s eFan setup not restricting access. That’s a nice little bit to know as labor charges go down a little bit in shops on those items. Something to think about for the maintenance a rig will need to for you to be able to drive it another 100k. I do most of my own repairs and maintenance so I definitely appreciate the eFan setup and the easy access to everything in the engine bay. There were some other changes that the 2005s got to address issues as well that I can’t remember off the top of my head.
Next on the list is that a 4 wheel drive transfer case equipped with 2HI, 4HI, and 4Lo and in the case of these rigs, an auto-4 option, was not an option from the factory in these trucks. There were a handful of 2005 regular wheel base Escalades built in 2005 with the 5.3 V8 with only rear wheel drive. I believe it was only offered on the regular wheel base and NOT the ESV trucks. Every ESV I’ve come across from 2003-2006 The regular wheel base Yukon Denali and yukon xl Denali are all full time all wheel drive transfer cases with no selectable ranges. With that being said the all wheel drive in my Denali is awesome. In the summer it cruises up and down the 7,000 feet in elevation gain of mountain roads I live on pretty damn well for a nearly 6,000lb vehicle. As far as inclement weather my truck sees it all! Sunshine, rain, snow, everything. This year our mountain ski town saw 10 feet of snow in just 10 days in late February. We never get that much snow all at once! It was so bad at one point that all three highways in and out of town were closed because CalTrans just couldn’t keep up with the sheer volume of snow. And through all of it my Denali plowed through with no issues even with no low range in the transfer case. The right set of tires and the all wheel drive will take you most places.
As for the GMT900 platform rigs. I like them as well and while they ar Elrond to some issues overall I’d say they’re still very reliable rigs. There are many ways to work around the AFM system issues. The range device shuts it down in the computer but has to be left plugged into the trucks OBDII port at all times. It’s a cheaper solution but works. Another option is to have it shut down in the computer via a tune thorough HPTuners, blackbear performance or similar. Pricier option but then you get to play with more parameters of how the truck operates rather than just shutting down the AFM system. And no need for the range device to always be plugged in. You can also do an AFM delete with invoices replacing the system with non AFM lifters and such. Pricey but a good option as well.
The GMT900s are still fairly easy to work on and they’re very nice rigs. Comfy interiors. Though personally I think the seats in my 2006 are better. The big upgrades being the 6.2L V8s which are stupidly awesome engines and the 6 speed transmissions mated to it. While my 4L65 trans isn’t terrible, the 6L80 would make towing better and easier for me up and down the mountains and better fuel economy. But oh well... Lol. The GMT900 Denali trimmed Yukon XL, and the Escalade ESV were also NOT offered with a 4 wheel drive transfer case. They were either built with rear wheel drive or all whee drive transfer cases. However the rear whee drive units were much more plentiful in this generation. The single and 2 speed 4 wheel drive transfer cases were only offered on non Denali Yukons and Yukon XLs same as the GMT800s.
I have tons of detail clients running both generations and they all love their vehicles. I’ll be in the market soon for a 900 series Denali XL or an ESV soon and I wouldn’t hesitate to buy a higher mileage rig. There’s so much knowledge widely available on this forum that I feel I can tackle any issue that comes up. I already can do that with my 2006 and I’m very thankful that I can say that.
I highly suggest you check out these two threads, most of the info you’d want to know about either generation can be found in these threads:
Ok guys I dont own one of these trucks So I need ALL of the info you can Admin has seen Fit to Create a Catch all thread for the countless "looking to buy" threads that go unanswered because lets face it some are repetitive. Hopefully people will read through this sticky and have all or most of...
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Gentleman I have been put in charge of making a sticky with common questions asked on the forum. These include common problems (please provide fixes and pics), some of the common mods (provide pics, step by step instructions, etc.) i.e. not air ride but maybe leveling the rear or front. I am...
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