Towing with a Colorado...Again

Absolutely correct.  12 mpg with the trailer and 20s without is better than teens all the time.  I will add some spring to the back, put in a trans cooler with a thermostat and maybe add the V8 radiator for more capacity.  Have a scan gauge so I can watch fluid temps.  

As far as the wagging, that was over a bridge with bad crosswinds.  The trailer came with the load bars and a sway control but it isn't set up for my truck and my springs are rather soft.  So maybe a bigger truck would be a more comfortable tow the colorado will get used for the first year. 

Checked in a trailer forum, people with the same size trailer are getting similar mileage numbers unless they are using diesels or 2 year old trucks.  Neither is a cost effective choice IMHO.

MINIzguy said:

Brake_L8 said:

I had no idea the Colorado had a 4L60, always thought it was a 6-speed auto. Shows how much I keep up with newer GMs. Anyway, as others have said, your frontal drag from the enclosed trailer/camper will be the biggest issue. I had a 2005 Yukon Denali with the 4L65 (functionally, similar to the 60) and towed my racecar with it in Drive. Never bothered using 3rd or 2nd unless I encountered a hill and either wanted engine braking or to keep the transmission from hunting in and out of a gear.

For all the E36 M3 the Denali put me through, the transmission was never part of the problems. Bought it at 125k and sold at 150k with no issues there. By the end, it would (very) occasionally stumble a bit between 1st and 2nd.

For your Colorado, I would leave it in Drive and just let it do its thing. You should feel the torque converter lock up in 3rd and/or 4th - on these transmissions it can almost feel like another gear change. If it's flat enough and the converter is locked, leaving it in 4th shouldn't cause any overheating issues. Don't be afraid to use the shifter though, and pop it to 3rd if you get to an incline where it can't decide what's going on.

If you are getting some "tail wagging the dog" sort of feeling with the trailer, check your tongue weight and tire pressures first. After that, well, enclosed trailers affect trucks more than open trailers do. You've got a big parasail that you're trying to drag down the highway and it will catch the wind with the big sides. The Colorado should have a long enough wheelbase to help with some of that. How long is the trailer overall? I'd be more concerned with that vs weight if you are not feeling super stable.

From what I understand, you don't get lockup in 4th on a 4L60, hence why people use 3rd

Any 4L60 made from 1998 onward will begin to get torque converter lockup as low as 2nd gear, with full lockup coming around 54 mph. Source

More info from a transmission tech on the Avalanche Fan Club site:

 In 98 GM went to a different strategy called “Ec3”or electronically controlled capacity clutch.
This strategy has made a big difference in fuel economy by starting the apply of the Tcc at much lower speeds and continually slips until it reaches highway speeds. It begins to apply in 2nd gear and slips up to 250 rpms depending on speed and engine output. In order for this strategy to work a new converter clutch lining had to be developed to withstand the slippage and heat generated. What GM came up with is a woven carbon fiber material that is very porous that allows fluid to flow though it for better heat transfer. This stuff is practically indestructible. 

In reply to Brake_L8 :

Yes per your link and post that was my understanding as well. The 4 speed was designed to handle most work in D. Driving in 3 would only be for a long grade or very hilly area.

I guess that is here nor there. It isn't like your MPG will double. Getting a nice diesel Colorado may be the optimal alternative to the full size truck route. If around town size is important.

porschenut said:

No, many colo people said the trans overheats in D, keep it in 3.  I'm concerned about engine life if it is burning that much fuel.  I can put the V8 radiator in, trans cooler would be a must.  The manual has no mention about trailer frontal area, but that is a great idea to research. 

The trans will overheat because it doesn't run fluid through the cooler in overdrive, unless they have changed that across the board.

Letting the trans bang down to 3rd under load is also not good for longevity, although modern torque management techniques should help.

Still, it's easier to just leave it in 3 and know it'll be okay.  Don't worry about the engine, engines are happiest under heavy load.

porschenut said:

In reply to joey48442 :

 

Newer tires, but 2wd so sucks in the snow.

First time I've heard that said around here.

Sonic said:

Harrisburg to philly on the Pa Turnpike is totally not flat at all, not even close.  Lots of small hills up and down the whole way.   Flat is like Iowa.  

Wow, you typed exactly what I was thinking.

Update for this week.  I am not real smart about towing capacity calculations.  What I learned yesterday has me concerned.  The payload for the truck is 1200, and I will be right up against that.  Here are the numbers:

300  boat and ladder rack.  Its a 19' hobie trimaran

100 two recumbent trikes

350 two people and misc crap

400 trailer tongue weight

1160 total, almost no wiggle room.  

So the tow weight means nothing, frontal area of the trailer is the load factor and that is on the high side.  Between these two I am thinking the Colo would do it but not well.  Rather then spend money on heavier springs and a trans cooler it makes sense to sell and buy a half ton.  Gonna put the colo on craigslist today.

If you use the Bernoulli Equation you can see that 65 mph has 17% more drag than 60 mph.  Its doubled by 84 mph.  Its a V^2 comparison.

 I am thinking the Colo would do it but not well.  Rather then spend money on heavier springs and a trans cooler it makes sense to sell and buy a half ton

Well, you sought out your information and made a reasoned decision. So far so good! Are you gonna make a 'what truck' thread or shall we bench race that here?