Best suburban base to start with?

[Luckie1999]

Suburban mafia,

I've been skulking on this forum for awhile, and decided on a GMT800 for my first non-daily driver overland/camping/hunting project rig with some help from some knowledgeable posters.

I've been looking for what I think is the "perfect" base for about a month and almost pulled the trigger a couple times but each time it was missing some stuff.

So...I'm back to ask your wise opinions again, what would be your "must haves" for a base Sub project and what would be some "nice to haves" that aren't deal breakers or could be easily/cheaply modded later?


For a reference, here is what I have been focusing on based on what I think I need:

Must haves:
150k miles or less
Reasonable price (assuming in my initial buy budget I'll have to spent ~2k on a new tranny)
G80 rear end
4.10 gears (want to put a 2-3 inch lift on for a modest increase in tire size, maybe 33s?)
"NZZ" skid plate package
2nd row bench seats (so I can take out the 40% side and still sit two kids in the back)


Nice to haves:
front row jumper/bench seat (more room for the wife or the dog)
Barn style rear doors (cuz they are cool and make for good fold down tables)
White (cuz subs look good in white)

Bonus Question: For non-towing applications is the 2500 with the 6.0 better then the 1500?

 

[CampStewart]

2500 is going to have better coolers, a much stronger transmission, and a much stronger rear axle. G80 is known to fail with bigger tires and hard use. I would opt for open rear and add an aftermarket locker.

 

[Luckie1999]

CampStewart,

Thanks for the feedback. I thought I read somewhere that the 2500 can also fit larger tires at stock then the 1500. Do you know if that's true?

 

[Jacobm]

I've got a 2500, and while I'm very new to overlanding, I think I made the right choice. The 6.0 and 4L80 would be pretty understressed if not towing, and There does seem to be plenty of room for tires. 33s would probably fit fine, I've got 32s with plenty of room. We'll see how much space there is once I crank the torsion bar and level the front out. We'll see if I break the G80 or not.

2500s also come with much better brakes, which I appreciate. I used to have a GMT800 Silverado 1500 and the brakes left a lot to be desired. The 2500 brakes are pretty grabby and bring the truck to a stop quickly.

The skid plates on the Z71 1500s are fiber reinforced plastic I believe, which is great for scraping the parking bumps at the mall and not much else. Worth looking into but I'd move that to nice-to-haves and not a must have if it were me.

 

[glock7018]

Another vote for a 2500 base one. The 6.0 and 4l80 is so much better than a 5.3 and 4l60. Also the 10 bolt rear end in the 1500's is comically small for such a large SUV.

 

[ExplorerTom]

This Ford guy finds it hilarious that you’ve budgeted for a replacement transmission up front.

I’d also go with the 2500. Or an Expedition or an Excursion.....

 

[Martinjmpr]

Well, you're looking for a unicorn for sure. The newest GMT-800 (2006) is now 13 model years old so finding one with < 150K is going to be tough. Front bench seat means lower trim level (base "fleet" model or LS) which is fine as long as you're OK without nice touches like heated seats and steering wheel audio controls.

2004 was the last year for barn doors.

4.10's in a 1500 are not common from what I've seen - 3.73 seems to be the standard (that's what mine had.) If you hold out for a 2500 you likely won't need to worry about the transmission but if you want one with low miles you're probably looking at $10k + for a vehicle that's almost 20 years old. From what I've seen the 2500's tend to be more "utilitarian" than the 1500's which were mostly sold to Suburban soccer moms and dads while the 2500's were often fleet vehicles. I would estimate that in the GMT-800 range there are probably 20 1500's for every 2500 you'll see.

Besides the transmission there are some other known issues like stepper motors in the dashboard (I had mine rebuilt with LED's and they added a transmission temp gauge for about $300), and whatever you get, before you take it off road even one time make sure you can get the spare tire down. The GMT800's had this hideous thing called a "secondary latch" that frequently rusted shut and would put you in a position where the spare tire will not drop, even if you cut the cable holding it up. I ended up removing mine with an angle grinder in the driveway and replaced the spare carrier with one that doesn't have the secondary latch (easy to do and pretty cheap) but I'm sure glad I discovered that in my driveway on a sunny afternoon and not in the middle of the night by the side of the road.

 

[XJLI]

What kind of roads/trails are you looking to tackle? Towing? Hauling a huge amount? Yea, a 2500 is cool, but 12 mpg isn't. A 1500 with with a little budget boost and 33s will kiss 20 MPG highway; and 1500s have a pretty high payload relative to everything else people load out on these forums. These truck are old now. Find the most well maintained, example with the lowest mileage (not necessarily just low miles) you can afford. People will balk at the newer trucks not being as "simple", but if you can up your budget get a 09+ with the 6spd auto.

 

[Martinjmpr]

What kind of roads/trails are you looking to tackle? Towing? Hauling a huge amount? Yea, a 2500 is cool, but 12 mpg isn't. A 1500 with with a little budget boost and 33s will kiss 20 MPG highway; and 1500s have a pretty high payload relative to everything else people load out on these forums. These truck are old now. Find the most well maintained, example with the lowest mileage (not necessarily just low miles) you can afford. People will balk at the newer trucks not being as "simple", but if you can up your budget get a 09+ with the 6spd auto.

20 MPG on the freeway? Yeah, OK.

Nobody's a bigger MPG data geek than me. I've been tracking it since I got my first vehicle in 1979.

On TWO occasions I was able to get 18 MPG on my '04 Suburban. The first was an all-day driving trip through the mountains with the wife, scouting out campsites. Nothing in the truck, not even the 3rd row seat. No cooler, no camping gear, no extra clothing. Just the wife and I (didn't even take the dog) and I kept speeds below 65 mph. For all that, I ended up at 18 MPG. The other time I had to drive to a town 200 miles away to get a sidecar for my motorcycle. I took everything out of the back of the truck and folded the seats flat so I could slide the sidecar in. I'd guess the sidecar weighed something around 125lbs, no more (two people could move it pretty easily.) Straight out, 200 miles and straight back, 200 miles on mostly 2 lane State highways with the cruise control set at 60 mph or less, I eked out 18.5. That's hand-calculated (although FWIW the dashboard gauge was surprisingly accurate.)

Around town? I averaged 11 MPG if I was lucky. 10 if I wasn't (cold weather/winter gas/heavy traffic, etc.) Starting and stopping a 5500lb vehicle requires a lot of fuel.

That was actually surprisingly close to the EPA estimates for the GMT-800 Suburbans which was 12/18.

It's not realistic to expect this generation of Suburban to return 20 MPG in anything but a one-off test under absolutely perfect conditions and zero payload.

I suspect the newer generations of Suburban with 6 and 8 speed transmissions and correspondingly lower rear end ratios, as well as multi-displacement technology, can probably reach 20 MPG on sustained highway trips, but they also cost $50k and upwards even on the used market.

 

[60beforetruck]

I vote for a 2500 suburban. Some had 4:10 from the factory. Like others have said. Get a " lunch box locker" for the rear. 8.1 is nice but, the 6.0 has more after market support and often more parts on the shelf at the parts store.

Once you have a 2500 you will like it.

 

[rayra]

The Z71s have a thick fiber-reinforced plastic chin piece, good enough to take some road debris on the highway. They have a larger ~3/16" thick aluminum plate that covers the front diff and engine area. And a heavy steel plate protecting the transfer case front driveshaft lobe.

Seconding the 'unicorn' remark, going to be tough to find that specific combo of features.

If you plan towing, go with the 2500 series and the 4L80 trans. Engine size doesn't matter much unless you intend to tow quite heavy. The key issue with the 1500 series / 4L60 seems to be differential heating of the steel and aluminum parts in the trans. Drive the trans temp above 275F and you kill it. We've towed often in the 2000-4000# range and have done fine. With the Tow/Haul option and its changes in shift points, it's really easy to tow those loads even with the 5.3L. Heavier loads, bigger mountains, you'll want the 3/4, 4L80 and a 6.0
1-2yrs ago I put a large trans cooler on mine and even on long grades with moderate tow loads, I rarely exceed 40F over ambient. Almost too much trans cooler. Given that I'm in the desert southwest I'm fine with that idea though.
Just 48hrs ago I hauled a 5x12 open tandem axle trailer over the 4000' Grapevine pass, with a partial load of furniture. Maybe 1600-1800#. And returned with a large refrigerator. Trailer towed like it wasn't even there, even on the steep grade of the return leg. Now that pass was closed due to snow in the preceding 48hrs, temps were in the 30s and 40s, but even going up the steep return my trans temp never exceeded 100F.

I'm a lead foot, I never top 14mpg. And my average tank mixed driving is ~12.5mpg with me speeding around in the high 70s on highway runs mixed with local stop and go.

Frankly the GMT800s are getting long in the tooth. The 900s are still highly priced, despite being 10-12yrs old. But they are still body on frame. Avoid the early / 2007-2008 Active Fuel Mgmt versions and even the later years, get that programming deleted / deactivated. They fixed the metallurgy in the cylinder bores to compensate for the accelerated wear of pistons and rings flopping around with no combustion pressure, but there's still potential for damage with the AFM. Maybe a 2009-2013.

But the 800s are still a good value, especially if you can turn a wrench or are readily able to pay someone else to. Parts are widely and cheaply available. Especially great as a third / dedicated special use, not a daily driver. There's a mid-series split, 2001-2002 and 2003-2006, the later have dual zone air in the front, seat warmers, more digital driver info and a computer-controlled throttle relay, no direct cable from gas pedal to throttle plate. Be sure to adjust out any slack in the throttle cables when you buy used.

We sold off our '05 Z71 K1500 Tahoe 14mos ago right at 200k mi. Daily commuter, 95% highway miles, was still in very good shape both cosmetically and mechanically. I'd done a bit of repair work on it, and my GMT800 Sub, detailed in the topics in my sig. We also owned a '99 Z71 K1500 Tahoe, traded in towards the '05. Both Tahoes bought new. My '02 Z71 K1500 Sub was bought 5yrs ago with 116k, I'm scarcely over 145k now, had a variety of niggling troubles with it, mostly due to poor maintenance by previous owner. No problems that I'd consider 'major', no breakdowns. But I'm also a fan of preventative maintenance and have done a lot of work to 'baseline' the vehicle when I got it, changing ALL fluids, all 100k maintenance, a full fresh of all the steering and suspension components, a few upgrades. And any time I'm taking much of something apart I'm looking for other 'targets of opportunity' to replace while most of the related work is being done already.

 

[XJLI]

You guys are at altitude and deal with mountain passes regularly. My commute is 75% stop and go and I average 14-15 in my truck with a little lift and larger tires. On long highway trips I'll hit 19. My neighbor has 275k on a 05 Z71 Tahoe he bought new and he gets 22 on road trips loaded keeping a light foot. My father in law's '17 1500 will get 25 highway easily if you baby it.

 

[CampStewart]

How did this thread turn into fish stories about who gets the best mpg? I am waiting for someone who swapped in a diesel and gets 30mpg towing to chime in

 

[nitro_rat]

Must haves:
150k miles or less - these trucks are old, buy on condition, not miles. One that's nice with 300k on the clock has been maintained and will probably have less issues that a 100k mile truck that's sat in someone's yard and never had anything replaced.


Reasonable price (assuming in my initial buy budget I'll have to spent ~2k on a new tranny) - yes, I wouldn't spend more than $3500 on one of these.

G80 rear end - I like them and they aren't problematic on the 3/4 ton models like they can be on the 1/2 tons.

4.10 gears (want to put a 2-3 inch lift on for a modest increase in tire size, maybe 33s?) - if you're going 33's I would re-gear to 4.88 but that's just me. Stock tires and 4.10's are a nice combo.

"NZZ" skid plate package - easy and cheap to add from junkyard parts

2nd row bench seats (so I can take out the 40% side and still sit two kids in the back) - yes, i hate the 2nd row captain chairs for many reasons!


Nice to haves:
front row jumper/bench seat (more room for the wife or the dog) - i agree.

Barn style rear doors (cuz they are cool and make for good fold down tables) - while i prefer barn doors to a tailgate on older suburbans the liftgate is nice. I would be satisfied with either.

White (cuz subs look good in white) - i'm not picky about color.

Bonus Question: For non-towing applications is the 2500 with the 6.0 better then the 1500? - yes, better brakes, transmission, more power!

 

[CrazyDrei]

Opened up a can of worms here my friend.

Everyone that commented is correct. Some are obsessive number crunchers that have been tracking MPG wince 1979, some are wishy washy dreamers that think that a 3/4 ton frame, 6.0 and 4L80 transmission is god's gift to automotive industry.

So to answer your question plain and simple as to which GMT800 to get is: YES.

1500 is a great platform, if you find one with the towing package, it has a bigger transmission cooler which according to many will prevent the transmission from exploding by looking at it, LOL.

2500 is a wishy washy overkill that only a fraction of people out there need the capabilities to TOW 5-10,000 LBS on daily basis, in that case you are looking at a wrong truck all together, get a diesel.

I have both a 1500 and 2500. 1500 is my baby, I have beat the living daylights out of it for the last 5 years, have driven it to Alaska and back twice, 190k miles in 5 years. 50k miles of HARD desert miles. I have 3" body lift on it and 37" tires. Couple more functional mods which allow me to comfortably run 2-3 day Death Valley off road trips in one day with two toddlers in the back that are rocked to sleep by the smooth 60-70mph ride over the worst washboard you have ever driven.

I would never dream of torturing myself or my kids by even thinking of taking the 2500 on the same off road trails, and if I did I would give my self 4-6 days to drive the same 300-400 miles around Death Valley. I do tow a close to 10,000 lbs trailer every week with it and it does very well. I would never dream of even hooking up that trailer to my 1500 to move it around the yard.

GMT800 Suburban/Yukon XL is a perfect platform for what you are expecting to do with it. I would change your must have list slightly.

Must haves:
150k miles or less
Reasonable price (assuming in my initial buy budget I'll have to spent ~2k on a new tranny)
G80 rear end
4.10 gears (want to put a 2-3 inch lift on for a modest increase in tire size, maybe 33s?)
"NZZ" skid plate package
2nd row bench seats (so I can take out the 40% side and still sit two kids in the back)

SOUTHWEST truck = virtually no rust even for 20 year old rigs.
$3-5k should get you what you are looking for
G80 rear end is fantastic
forget 4.10 gears, do not fear the gear, I ran 3.73 in a 98 suburabn with 35s for years, never had any issues
forget the skid plates, its extra weight, if you actually need them you should not be looking at suburbans. I took all of mine off years ago, crawled some trails my buddies with Rubicons didn't want to attempt, never had issues
forget the bench seat, take the first truck with under 150 miles, no rust and under $5k that you find, bench or buckets are $100 on craigslist, 6-8 bolts and 30 mins to change.

Nice to haves:
front row jumper/bench seat (more room for the wife or the dog)
Barn style rear doors (cuz they are cool and make for good fold down tables)
White (cuz subs look good in white)

Lucky for you the front row jumper seat for GMT800 trucks is $50 on eBay or craigslist, takes 30 minutes and 4 bolts to change.
Barn doors are way better than my lift gate, however from the practical point lift gate offers protection from the elements that the barn doors do not. As Martinjmpr said 2004 was the last year of barn doors.
$100 and a day with a heat gun you can wrap your truck any color you want. Rustolium and paint roller will get it looking white pretty quick too.

Bonus Question: For non-towing applications is the 2500 with the 6.0 better then the 1500?

Non towing: 1500 is better. 2500 has heavier duty parts but they are such an overkill for a "non-daily driver overland/camping/hunting project rig" that they are just not worth it, unless you really think that leafs offer a smoother and better ride than coils.

And to side track you even more, what is your budget? I regularly see 200k mile GMT900 trucks with a much better 6L80 6 speed transmission pop up for around $3-5,000. Wouldn't it be nicer to have a truck that is 10 years newer and has been run on nothing but highways for the same price?

What ever you end up getting make sure it makes you smile and want to drive it what ever your reason might be and don't forget to post some pictures, we like pictures!