Trailblazer with 5.3 or go with the Tahoe for towing? Same general years...2002-2006

c good

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Dec 8, 2011
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My Envoy does OK towing my 14 ft trailer. It struggles a little on grades when fully loaded with the trailer and add'l camping cargo. Firewood, chairs, etc..... I am thinking the 5.3 might be better. Also, does the Tahoe have the 4L60E with a "Tow Haul" button? Also, how much difference is there between a Trailblazer EXT with the 5.3 vs the Tahoe towing wise, inside cargo space, etc. Thanks for any input.
 

littleblazer

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Jul 6, 2014
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They both weight about the same, they both have the same power in V8 configuration, the Tahoe should have tow/haul on the shifter. A regular tahoe has a 113 inch wheelbase, burban a 130 inch and an EXT 360 129 (regular is 113). Longer wheelbases tow better to an extent. Interesting thing, while the tahoe is rated to pull more, the payload is about the same as a 360 or 100lbs more. So as far as gear plus tongue weight and the such, you really aren't gaining a whole lot. Now interior wise you will have more room on the fullsize. Turning radius is comparable between the two, outward visibility is great between the two too. A fullsize with a 5.3 is an easy find and will likely be able to choose from various conditions... a 360 with a V8 is like hens teeth.
 

Mooseman

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Dec 4, 2011
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And I think MPG wise, there is no difference. And like @littleblazer said, V8 360s are hard to come by.
 
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TollKeeper

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That, and if you can find one, a Isuzu Ascender Limited will be loaded just a well as the Denali, and be cheaper!

There are more XUV's out there with the V8 as well, but you do have the issue of the XUV specific problems.

Edit- Wow that XUV is paint burned!

Edit2- There is a catch with finding a V8 model GMT360.. 2006 and up have DOD/AFM
 
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Mooseman

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That Ascender is pretty reasonable and seems to be in really good condition except for the paint. And the XUV, as @TollKeeper said and knows, parts are basically non-existent for the XUV specific stuff except used, which are basically as reliable as the ones you're replacing. They do have a cool factor though.
 

TollKeeper

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The big thing for pulling a trailer is gearing...

A GU6 3.42 is a fuel mileage gear, sucks for pulling trailers. My XUV has this gear. I even hate it for city driving. Great for highway cruising, as long as there isnt a trailer.

A GT4 3.73 is a great city gear, and does good pulling a trailer. My Saab has this gear.

A GT5 4.10 is a power gear, great for city driving, but sucks for fuel mileage. Awesome for pulling trailers thou.

I am all about the power, and would love a GT5 4.10, but at the end of the day, a GT4 3.73 is probably the best gear for these.

And with the Isuzu, it is a rebadged Envoy, everything is completely interchangeable!
 
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c good

Original poster
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Dec 8, 2011
526
Great info LittleBlazer, Mooseman, Northcreek, Tollkeeper. I appreciate all the input. I'm actually leaning towards the Tahoe because it has the 4L60E transmission with the "Tow Haul" feature. Something that none of the 360 platforms offer.

What are the thoughts on an older Tahoe....1997-1999 with the 5.7 vortec vs the 2000 and up 5.3 vortec? My understanding of the 5.7 is that it is not prone to the oil ring seizure problems of the newer 5.3 and the 4.2 design pistions.
 

Sparky

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Dec 4, 2011
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I wouldn't worry too much about the AFM side of things if you get a newer one, just tune it out. That's what I did on my 5.3L Silverado and no real problems at 237k.

I don't know about any oil ring seizure problems on the 5.3 or 4.2.
 

Mooseman

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Dec 4, 2011
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IMHO, the LS based engines are far superior to the old small blocks in all respects. Would you really want to stay with a 50 year old design? It's OK but the LS was created for a reason. Heck, even the 4.2 beats the 5.7 in HP (270 vs. 255) but not torque simply because of displacement and number of pistons but if we were to compare per L, the 4.2 made 65.48 ft/lb per L while the 5.7 made only 57.9 ft/lb per L. If an I8 Atlas would have been created, it would have been 5.6L and would have made a theoretical 367 ft/lb and 360 HP.

A 2002 5.3 makes 285 HP and 325 ft/lb compared to the 1999 5.7 255 HP and 330 ft/lb. Torque difference is minimal but clearly the 5.3 is way more efficient with the smaller displacement.
 

littleblazer

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Jul 6, 2014
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Having towed with both a 5.3 and 5.7 they do about the same. The CPI setup on the vortec 350 is problematic. I'd probably go for a 5.3 only because the chassis under it is going to be superior....
 

TollKeeper

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I think you are making a good decision on the Tahoe/Yukon/Escalade/Avalanche/Suburban.

The bigger interior is more comfortable for trips, and the wider body/axles is more stable for towing.

Not sure how big that trailer is on weight.. But if its really heavy, a Suburban/Yukon XL 2500 with the 8100 is a thing to look for.. if you can find one!

Or find a Yukon Denali or Escalade with the 6.0. Beast of a motor!
 

c good

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Dec 8, 2011
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Tollkeeper...the trailer is a Geo pro G14FK. Small but perfect for my mild off road desert adventures. It has good ground clearance with the added lift. It weighs 2000 lbs and has approx 1000 lbs storage for max gross of 3000 lbs.

Mooseman.....how awesome an I-8 Atlas would have been! Long nose....but awesome! 😎👍
 
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TollKeeper

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3000 lbs? I mean almost anything can pull that one.

Before you can your Envoy, whats your gearing in it. If you have the GU6, just doing a gear swap, and getting @limequat to reprogram the ECM, and your set. Much cheaper.
 
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Mooseman

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:iagree:

If it just struggles a bit up grades, then a gear change would work. However, you have to remember you also have to change/replace the front diff.
 

Sparky

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Dec 4, 2011
12,927
GT5 will give you the best towing grunt, but will hurt your highway mpg the most when not towing. If my main concern was grunt, I'd go GT5. They're the hardest to find though I think.

What year is your truck again? That can also play in. Earlier GMT360s can't be tuned for tire size, not sure about gear changes.
 

TollKeeper

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Thats a good point.. I had forgotten on the early model GMT360 4.2 I6, a gear change is not possible because of the ECM.. Not sure when that changed. I know you can replace the ECM from the donor vehicle the axles came out of.

I would have to assume it was 2005 or 2006, @Mooseman or @Sparky would know more info on that one.

EDIT: If I am remembering correctly, you can tell if you have a programable ECM by your gear shifter. If under you main shift button, you have a second button to turn on/off Stabilatrak, than the ECM is programable.
 
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TollKeeper

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, I'd go GT5. They're the hardest to find though I think.
Actually, the I6 GT5 are easier to find. The V8 GT5 are harder... You cant just swap a SS rear since the drive shaft was shorter for them

I love the GT4 in my Saab.. I have a GT5 front diff, and its tempting to swap one of my trucks out once I find a rear diff, and have the time, and feel like tackling that front diff.. Just have not done it. I tow with both the GU6 and GT4, but my trailer is A LOT lighter. Maybe 1500lb. In the mountains I live in, the GT4 is the cats meow. But the GU6 is so much better for fuel mileage with and without a trailer.

At least in @c good 's case, he can use either a V8 or a I6 rear axle. And the V8 rear axle is preferred.

If you do decide to got the GT5 route.. I can sell you my GT5 front.

My trailer that I use to haul/store my 3 quads.
69571 - 2023 Triton Trailers TC Series 8x12 Enclosed **In Stock NOW!** Snowmobile  Trailer for sale in Forest Lake MN



EDIT: 02-05 are interchangable within that year range.
06-09 are interchangeable within that year range.. But can be used for the 02-05, a plug on the axle will not be used thou.

-Deleted- wrong info

My thoughts are kinda scattered at the moment, so hopefully thats clear, if not one of the other GURUS will clear it up.
 
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TollKeeper

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Yea.. The only way to do a axle change is to also change the ECM from the donor vehicle.

@limequat can confirm, but I am pretty positive on this.
 

Mooseman

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Dec 4, 2011
25,257
Ottawa, ON
02-05 can't be tuned for gear/tire changes. 06+ can. There may be a way around that though. I once had put in a mystery PCM that was for a 3.73 truck as my speedo was off. The only thing I can think of that can allow to change the gearing is to use the VIN of a truck with the desired gears. While programming PCMs, the programmer (i.e. Tis2000) doesn't ask what gear option to use. The only thing it asks is the VIN. May also need to reprogram the BCM and ABS because, at least for the ABS, it's also affected by the gearing.

I once spoke with someone that had the 4.10 gears and said that MPG weren't that bad. For the rear, it may be possible to just swap out the gears themselves but, from what I can tell, they're only available for the larger V8/EXT diff 8.6 gears. And it would also require the knowledge and equipment to be able to set them up properly. It may be possible to find a complete 4.10 diff but in the SWB i6 8.0 variety.

Might have to go with 3.73
 

Sparky

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Dec 4, 2011
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2006 was the computer change and when you could tune for gear/tire changes. 02-05 were stuck. I just dealt with my speedo being off by 10% when I put bigger tires on. (So really, my TB had a couple more k miles on it than the odometer read at its end. It said 215k but I think I had done the math and figured out it was closer to 218k or so.)
 
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c good

Original poster
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Dec 8, 2011
526
Took the trailer for a trial run today with the Envoy. I averaged around 12 mpg towing at 60-65 mph in 3rd gear. Mixed terrain, freeway driving. It actually did pretty well even on the grades. Is that about right for MPG?

I'm just not used to running it at 2500-2700 RPM.....but it seemed like it was handling it just fine. Not going to worry about any gear swaps for now.
 

TollKeeper

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Sounds about right for a GU6.

I thought there was a way to enable a Tow/Haul mode on the GMT360?
 

Mooseman

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Dec 4, 2011
25,257
Ottawa, ON
I thought there was a way to enable a Tow/Haul mode on the GMT360?
Not that I know of. It may be possible to tune in a tow/haul shifting pattern as the primary pattern however, because there is none for this particular engine with it's higher RPMs and torque characteristics, we can't use the tow/haul pattern from a V8 truck. And it's not just changes to up-shifting but also down-shifting for engine braking.

Did find this thread at TV:

And this one here:

I think PCMofNC does a sort of tow type of tune if you tell them to, which may be a sort of in between regular and tow/haul but it would be all the time. Could have been just for torque management. Maybe our resident tune god @limequat could chime in on this one.
 

Mooseman

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Dec 4, 2011
25,257
Ottawa, ON
Found another thread that talks about towing:

 

littleblazer

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Jul 6, 2014
9,265
I'd look into maybe adding a weight distributing hitch to that setup. You have a little more rear squat than I'd like to see. Otherwise I think you'd be just fine.
 
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c good

Original poster
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Dec 8, 2011
526
I was planning on installing the inside the coil springs airbags to help with the squat. Would the weight distribution hitch be better?
 

Mooseman

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Dec 4, 2011
25,257
Ottawa, ON
A WDH is better.


Another note that they don't mention is that a WDH usually has sway control. The Equalizer has it built-in however others it can be added.
 

c good

Original poster
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Dec 8, 2011
526
Excellent YouTube Mooseman. Thanks for finding that. I've decided to go with the WDH. Would it be worth getting the sway control for something this small? Where I camp in the desert is often windy while going through the passes. Sway control might be beneficial. Thoughts everyone? Thx...

P.S. I already bought the airbags so I'm thinking I'll install them anyways for when I'm not towing the trailer but am loading up the back with gear. Or using my Joe Hauler for the motorcycle.
 
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Mooseman

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Dec 4, 2011
25,257
Ottawa, ON
I think it usually comes with the WDH. Just to be sure you get the right one, you should talk to a specialist at a trailer or RV shop or at eTrailer. The Equalizer has it built in but it's pricey. That's what I have but I tow a lot heavier (25 ft, 6500#, 900# tongue). MAke sure the one you get allows backing up as some of the cheaper ones don't.

Found this vid that explains sway well:


And this one Showing 6 different ones.

 

l008com

Member
Feb 19, 2016
886
Massachusetts
This theads a little old, but not too old. I tow regularly and have a short wheelbase LT TB with a 5.3.

At the pump, it's not ideal. But the power is really nice. I also upgraded to stiffer front springs, and EXT rear springs, so its a stiffer ride all around. And it tows great. Most of my towing is light towing and I don't even notice the trailer. Including up to my boat, which is a 1900 lb load. If the boat trailer tires are fully inflated..... what boat?

I've towed heavier stuff too. A bunch of loads of asphalt and concrete this past fall, probably in the neighborhood of 3000 lbs. Handled it like a champ, on road, and on the unpaved roads in the quarry i was dumping at.

I also rented a 50' lift trailer once. It was 5000 lb and had its own trailer brakes. Stopped on a dime but that was the only time towing that I ever really felt sluggish. But I more than doubled my weight so thats to be expected.

All my other trucks were S10's with 4.3's so compared to that, this v8 is another world. I always think about this one particularly hill on i93 in massachusetts. I've towed my 1900 lb boat up that hill many times and I'd always end up doing about 45 mph by the time I got to the top. These days I tow that boat in the trailblazer and I'm usually in the left lane and accelerating/passing cars on my way to the top. The difference is DRAMATIC, much more than you'd think just looking at all the numbers on paper. But you weren't comparing to a 4.3 so that's not really relevant.

So just to reiterate, even 8 years ago when I bought mine, 5.3's are hard to find, especially in short wheelbase. But they're super useful, practical trucks that are excelent towers. And I find the interiors very comfortable, not cramped at all.
 

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