First impressions of the GMT-800 Suburban 1500 as a tow vehicle...

Martinjmpr

Wiffleball Batter
For the benefit of those who may be considering a GMT-800 series truck (Chevy or GMC, roughly 1999 through 2006 or 2007, depending on whether you are looking at pickups or SUVs) I thought I'd share my "first impressions" here.
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I got my new-to-me '04 Suburban back in December, the primary purpose was to be a tow vehicle for our small camper trailer Livia (a T@B Clamshell) that weighs around 2,000lb fully loaded (my estimate.)
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We got the T@B in December of 2014 and took it on 14 camping trips in 2015, which took us around our home state of Colorado and as far away as Niagara Falls and upstate New York, Capitol Reef in Utah and Big Bend National Park in Texas.
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It was obvious to me early on that while the V6 4runner was an awesome all-around SUV, it was less than ideal for pulling a one-ton trailer on extended highway trips. While the T@B certainly fell within the 4runner's 5,000lb "rated" towing capacity, it definitely felt the strain of pulling the trailer, especially up our high Colorado mountain passes. Power was adequate, but just that. Transmission temperatures would routinely climb into the low 200's if I was trying to climb even a relatively mild hill, and MPG was disappointing. Under absolutely ideal conditions I could get as high as 14.5 but most of the time while cruising at 65 I was averaging 12.5 - 13. Driving through heavy rain and wind across North Dakota - a flat state that you would think would yield decent MPG - I ended up getting between 10 and 11 MPG. Combined with the 23 gallon fuel tank this had me figuring on a maximum fuel range of 200 miles, which I consider to be very low, especially out West where gas stations can be far apart.
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Coming back from Canada in June I finally resolved to start shopping for another vehicle, something bigger (to accommodate the stuff we haul with us) and something with a more powerful engine. I didn't expect any increase in MPG but I didn't expect much of a decrease, either. Basically my thought went like this: If I'm going to get 12 - 13 MPG anyway, I might as well be in a big, comfortable vehicle.
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Because of camping commitments I didn't have the opportunity to sell the 4runner until after our last trip of the year, which was our Thanksgiving trip to Big Bend National Park. It was a fun trip, and we did some back country exploring in the 4runner, but it was kind of bittersweet for me because I knew it would be the 4runner's "last hurrah", at least with me.
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Our first camping trip of the new year was in early April, but that wasn't much of a "test" for the new tow vehicle as it was just 60 miles away to a lake North of Denver. Basically it was almost all fairly flat interstate drive, with one small hill just as we got to the lake (Carter Lake.)
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At the end of April, though, came the first "big" trip of the year, which was to Maybell, CO, in the Northwestern corner of the state, about 250 miles from Denver across multiple mountain passes including the Eisenhower Tunnel (11,000') and Vail Pass (10,650'.)
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Our first "test" was Mount Vernon Canyon - those of you who have passed through or live in Denver know this one well. This is I-70 where it climbs out of Denver and into the mountains. In the space of roughly 5 miles the road ascends about 1800', the kind of road where overheating is not uncommon and where VW buses putter along at 15 MPH in the right lane with their 4 way flashers on. The big 'Burb did very well on this section. While I certainly "felt" the weight of the trailer it seemed to go up pretty effortlessly, not downshifting to 2nd until it got near the top. Best of all was the transmission temp. On my 4runner it would routinely hit 215 - 220 on this stretch, even if I shifted the transmission manually. The Suburban's 4 speed trans never got above 180 and took the whole thing in stride. I had a similar experience climbing the grade from Georgetown to the Eisenhower Tunnel and climbing from Copper Mountain to the top of Vail pass.
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About the only negative thing I'd say about the Suburban's hill climbing with the trailer in tow is that it seemed to take a long time for the engine to "kick down" to a lower gear. However, I should point out that on the out-bound trip, I was not using the "Tow-Haul" mode on the transmission, basically as an experiment. For the trip back, I took a different route through Steamboat Springs and over Rabbit Ears and Berthoud Passes. This time I WAS using the tow/haul mode and it seemed to help quite a bit by making the transmission kick down to a lower gear earlier than it was without using tow/haul. Even with all these passes, the warmest the transmission ever got (according to the Scangauge II) was 194. I was very happy with that!
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The big, cushy seats in the Suburban are very comfortable for long distance traveling and it's nice to be able to make adjustments while I drive - with the 4runner that was not really practical. The leather is nice and soft and the wife LOVES the heated seats (good thing the one on her side works - the driver's side heater has been broken since I bought the truck.)
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Having the transmission shifter on the column was a new experience for me - although I've driven a lot of column-shift automatics (in fact I learned to drive on one), this is the first time in 35 years of car ownership that I've ever owned a vehicle with a column shifter. The column shifter kept the console area free for drinks and electronics (iPod and phones) which was nice (when I had the 4runner I often had to move cables out of the way in order to shift the gated shifter on the transmission.) One niggling little annoyance is that my Suburban has the well known "disappearing PRNDL" problem, i.e. the LED display for the transmission is going out. There's a relatively simple fix for this but I haven't gotten around to doing it yet. Without a good display it wasn't really possible for me to manually shift the transmission while climbing or descending a hill, the way I did on my 4runner.
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MPG was not spectacular but not disappointing either (I knew what I was getting into.) I haven't filled up yet since returning but it looks like my overall towing MPG is going to be around 13 - 14, which is acceptable to me, particularly given the 31 gallon fuel tank. What it means, essentially, is that except under the most extreme conditions I can plan on a comfortable 400 mile range while towing, which is almost double what I had to figure on with the 4runner (I used 250 for planning purposes.) This was one of my biggest concerns with a tow vehicle, having decent range.
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The overall "feel" while towing was also very comfortable. Where the 4runner often felt like it was "struggling", the Suburban just lopes along. The Suburban weighs nearly a half ton more than the 4runner did and is 30" longer overall, giving it a very solid feel. Surprisingly, for it's supposedly huge size, the Suburban really doesn't feel that awkward when driving on narrow roads or parking. Even turning around and backing with the trailer isn't that difficult.
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During this campout our little group took a day trip out to the Sand Wash Basin, an area of BLM land with primitive dirt roads, to see if we could see wild horses, which live in that area. They had just had several days of rain and snow so we were cautioned that the road could be very muddy in places. Well, it was but even with street - oriented (and cheap!) tires, the Suburban did very well in the mud and rough roads, slipping and sliding, for sure, but never even coming close to getting stuck.
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Anyway, those are my "first impressions." We have another big trip coming up in about 3 weeks that will take us all the way to the Seattle area and back to Denver, but so far I'm pretty pleased at the Suburban as a tow platform and mild off-roader.
 

1stDeuce

Explorer
I don't think a 2000lb tab really counts as "towing" to a Suburban... :)

Sounds like it's working out! Which is good for you!! Tow/Haul does downshift a bit sooner, or rather tries to keep the rev's up a bit more to keep the trans cooler. With it off, it'll try to hold gears longer to avoid busy shifting complaints. My '02 GMC 2500 doesn't do downshifting when slowing in tow/haul, but I thought later trucks did that... Just curious if your '04 will downshift early as you slow in Tow/Haul, to provide some engine braking... I assume it was something that going to electronic throttle allowed, as they could "blip" the throttle to make the downshift less harsh... Or perhaps it didn't come about in GMT800 at all... ?
 

rayra

Expedition Leader
We've never had any trouble with ours. The length, weight, stability of the Sub just can't be beat when it comes to hauling a trailer. Totally stable and the size of the vehicle itself seems to buck enough air that the trailer itself is drafting. We've hauled bowrider boats full of loose gear (inadvertantly) without losing anything. And hauling a 14' tandem axle U-Haul stuffed full of household goods out of the Sierras and up and down CA's central valley and over the 4000' Grapevine pass was no trouble at all. Use the Tow Mode, it's what it is there for and it does a fine job. I've also hauled Harley's in an open tandem axle trouble with excellent stability. Truly it's easy to forget you have anything attached.

haulhaul_zpsb38e6e55.jpg



The dash re-solder is easy, but you have ot use a very fine tip and be careful you don't overheat things. Just enough to re-melt the connections will do.

These two vids provided enough info to do our Tahoe recently.

https://www.youtube.com/watch?v=vStMcCHZuRM
https://www.youtube.com/watch?v=tGzlnrZL8k4
 

legendaryandrew

Adventurer
Blackbear tuning if you want a bit more performance and a far better shift feel. Most the 'burb owners here love their trucks, good to see another join the club!
 

Martinjmpr

Wiffleball Batter
Blackbear tuning if you want a bit more performance and a far better shift feel. Most the 'burb owners here love their trucks, good to see another join the club!
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I'm assuming this is something that plugs into the OBD-II port? If so, is there a "splitter" available? Reason I ask is that I run an SGII so the OBD is in use right now.
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I wouldn't mind a bit more "juice" and I've been contemplating maybe going to a fairly mild custom exhaust (Hey, if I'm gonna pay the fuel penalty for driving a V8 I might as well get that awesome V8 sound, right? :sombrero: )
 

justcuz

Explorer
I've got a 3" cat back exhaust on my 2000.
When going downhill and you let off the throttle it takes several seconds for compression braking to actually kick in.
Those big old mufflers they put on 2004's look restrictive, but I remember seeing one cut in two at a muffler shop and as I recall they are pretty wide open inside.
My daughters muffler on her 2004 Tahoe has a very open sound to it and you can almost hear each cylinder pulse at idle through the tailpipe. Almost more like a big resonator.
 
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Martinjmpr

Wiffleball Batter
I don't think a 2000lb tab really counts as "towing" to a Suburban... :)
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Yeah, I knew it was a bit of "overkill", kind of like using a sledgehammer to squash a bug (imagine what it would have been like if I'd been able to find a 2500 with the 6.0! :rolleyes: )* Still, I have to say I like the feel of comfort and safety I get from a big rig like that.
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I can tell already that the one issue I'm going to be dealing with is trying to avoid the urge to bring along everything we own because "what the hell, why not? There's plenty of room!" We brought our Camp Chef propane fire to the last two campouts and never used it once, same thing with my Coleman lanterns (I collect them and like to show them off.)
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Having all that space is definitely a mixed blessing. We tend to get lazy with organization and use the "just throw it in the back!" method of storage. :elkgrin: Which is fine until it's nighttime and/or raining and you need to find something that fell to the bottom and you're having to dig through mountains of stuff to find that flashlight, or zip ties, or tools. In that kind of circumstance, "more space" = "more places for things to get lost/misplaced/hidden."
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* When I was shopping for my 'Burb I found an absolutely cherry 2500 that was well within my price range, had low miles and was even in my favorite color (dark green.) But I didn't even consider it when I found out it had the 8.1. Sorry, I don't need a 496 cubic inch engine. :Wow1: Talk about "overkill!"
 

justcuz

Explorer
Truthfully if it is not a daily driver the 8.1 is not a bad engine. It works much less towing and the mileage is not as negatively effected.

I had a friend who went from southern Nevada to Kansas to pick up an Airsteam. His had an 8.1 and he was claiming 15 to 16 mpg towing!

I know he loved that Suburban, towed the trailer and hauled his Grandkids around in it. A tree fell on it in a windstorm and smashed the top down badly. Bent the pillars from the passenger doors to the tailgate.

He replaced it with a Ford crew cab with a 460 and he wishes he had the Suburban back.

Big blocks get a bad rap, the 8.1 is a completely different animal than the older engines.
 

ZMagic97

Explorer
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I'm assuming this is something that plugs into the OBD-II port? If so, is there a "splitter" available? Reason I ask is that I run an SGII so the OBD is in use right now.
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I wouldn't mind a bit more "juice" and I've been contemplating maybe going to a fairly mild custom exhaust (Hey, if I'm gonna pay the fuel penalty for driving a V8 I might as well get that awesome V8 sound, right? :sombrero: )

They're a shop that tunes your computer specifically for your vehicle and needs.

They specialize in GMs. http://www.blackbearperformance.com/
 

rayra

Expedition Leader
Martin it's a re-write of your vehicle's firmware, replacing your basic program. The fancier tuners sort of do it on the fly, using a dash-mounting control unit, allowing you to switch between your basic / factory settings and a 'performance' profile.
The basic reprogramming / replacement leaves your OBDII port open. And it's 'reversible'.
 

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