When my GMT400 isn't enough...

[scottydl]

I tow our 32' RV travel trailer (around 9000-9500# fully loaded) with my Burb 2500. It's got the 7.4L and 4:10 gears, giving it the largest available 10k# towing capacity for the GMT400 era. So it can do the job on paper and towing my trailer on flat isn't a big problem... but it really seems like it's working hard on any kind of hills and/or hot summer days. I tow in 3rd gear per the manual, resulting in extra-deplorable fuel economy at around 6mpg... but I know that's to be expected towing so much weight with a gas engine. But based on its performance around the Midwest, I can't imagine towing the trailer on any substantial mountain passes with this Suburban, which I would like to do someday. I want to take the family West (Yellowstone, Grand Canyon, etc.) for a long camping vacation in the next few years.

So what's my next best tow vehicle option if/when this GMT400 Suburban 2500 isn't enough? I'll be saving up and buying in cash, so anything new (or probably anywhere close to new) is out of the question. I really like the 3/4 ton Suburban option for 3-row seating / family hauling. The 2001-2006 similar option with the 8.1L had its towing capacity bumped to 12k# IIRC, but would that really be a significant upgrade in ways other than the engine? Or would I be buying trouble with the new(er) body style?

I'm not totally opposed to going for a crew pickup over a Suburban, but it would have to be a diamond in the rough that hadn't been abused and still had lots of towing life left.

(I read through this other recent Worth upgrading to GMT800 thread, good info but mostly smaller engine options were discussed there.)

 

[884x4310ci]

When a gmt400 2500 isnt enough. You get a gmt400 3500.
A buddy of mine has a 3500 double wheel thick spring pack with overload spings.And he fills it up plus haules a trailer with it. And it bearly squats.

 

[letitsnow]

Is your truck all stock moter wise?

 

[scottydl]

Yep all stock AFAIK. I like it that way overall but I'm not opposed to some upgrades if it would help.

And I guess my first preference is to find a 3/4 ton SUV option (leading me to a GMT800 Suburban or diesel Excursion) before going with a pickup. My Burb doesn't have a squatting problem. Stock suspension handles the tongue weight fine, and I also have Airlift rear airbags installed which improves the ride while towing (although it still gets pretty bumpy on rough roads). I also use a full weight distribution hitch and anti-sway setup.

 

[BNielsen]

Start doing little modifications, your truck being a 95 a good place to start would be a decent exhaust, and possibly finding someone who could burn a chip for it.

 

[likestrucks]

It can tow that load just fine, you will just be slow. If your Suburban is a 95, then its running the tbi 7.4, which was rated at 230 HP and 385 ft-lb. For more relaxed towing, you want more power. But really it can tow that load fine, but you will be slow. By contrast the 1996 got the Vortec 7.4 that was rated at 290 hp and 410 ft-lb. The 8.1 in the 2001 was rated at 340 hp and 455 ft-lb. That difference in power makes quite the difference.

We had a 2001 2500 Suburban with the 6.0, and towed a 10000 trailer for 8 years with it, and it did fine. A little slow on the steeper grades but enough for what we needed. The 6.0 was rated at 320 hp and 360 ft-lb. I am not sure what problems you reference with the GMT800 problems, but that 2001 Suburban is still in the family and is still running great.

With a GMT800 Suburban with the 8.1, you jump 110 hp and 70 ft-lb of torque. It will tow completely different then your 95. But if your 95 is in great shape and you like the rest of the vehicle, you could consider some performance upgrades to bring the power up. Exhaust and a new chip burned for the computer. If you want to dig into the engine, you could have new heads and a new cam installed to wake it up.

Or you could drop a Gm Performance Parts Crate HT502 into it. This engine was designed to be a replacement for tired 454 applications in trucks and heavy haulers. Its rated at 406 hp and 541 ft-lb of torque. But that power rating isnt a fair apples to apples with the ratings above. The ratings of a engine in a production vehicle are after the losses associated with accessories and exhaust. Crate engines are rated typically with no accessories and open headers. So realistically that HT 502 probably comes in closer to what the 8.1 does power wise.

 

[Schurkey]

Pre-DEF Duramax, 2005--06. More tow-friendly engine, more tow-friendly transmission.

 

[884x4310ci]

Well if your only problem is in the power department. Put some motor upgrades if your willing to.
Edelbrock makes a nice top end package for these TBI 454's
Might be worth looking in to.

 

[scottydl]

Good discussion all. Keep it coming!

I'm not sure I absolutely LOVE this Suburban, but I do like it a lot and physically it's in great shape. I'm the 2nd owner and the original owner babied it, rustproofed and undercoated yearly so it has almost no body rust. Mostly I like the price I paid (under $5000) and the fact that I'd probably get most of that back upon selling, as someone mentioned above. For fun I looked up a few 05-06 Duramax Silverado's, and was pretty happy the first one I saw was priced around $9900... but then I saw it had 301k miles. Haha, no thanks! Any decent miles (100k-150k) bumped the prices to $15k-20k which is more than I'll pay for something that I only tow with a few times per year.

I don't mind checking out some upgrades to my 95's 7.4L, but I've kinda outgrown big roaring exhaust and I have to decide how much is really worth putting into upgrading a sub-$5000 truck with over 115k miles. Googling top end kits was showing prices around $2600-2900 (not including installation)? I couldn't justify that. The Burb IS in really good shape for 25 years old, although maintenance/repairs averaged $1000 annually over the 4 years I've owned it. The more expensive things (tune-up, brakes, suspension parts, fuel pump) shouldn't need to be repeated for years to come since I don't put many miles on it.

Decisions, decisions.

 

[Tavi]

The number one problem with the TBI big block is low compression. Rated at 8.5. Some have measured out to as low as 7.5. GM did this to combat NOX emissions.
Number two problem is the tiny cam GM installed. Again, to combat emissions.
Next is the restrictive exhaust. GM just being lazy.
The final hurdle will come from the TBI system itself.
As a tow vehicle, the heads will flow enough. As will the TBI. Don’t expect anything over 4500 RPM.
Compression will be the hardest and most expensive thing to increase.
Cam, tune and exhaust will help a lot too.
But if you don’t love the truck. An additional $2-3000 to make it run a bit better probably isn’t in the cards for you.

As a side note. I’ve crossed the scales at 17,500 lbs. I had no issues getting or keeping speed, even on some better hills. Although it wasn’t an enclosed or RV. Which does add a drastic amount of wind resistance.