Anybody towing with a Chevy,6.0 K2500?

[Grit dog]

It will tow your TT ok, but not stellar.  No way 12mpg towing.  More like 12-14empty and <10towing.  Nothing wrong with the truck or engine, they just don't make good torque down low.  They need to be wound up to pull hard.
I'd hone in more on a 8.1/Alli combo.  Your gas mileage won't really suffer at all compared to the 6.0 and it will pull like an older diesel but not as good of mileage.  Plus the Alli is twice the trans the 4L80 is or whatever the lighter trucks have.
Edit: my exp with these trucks is at high altitude, so you'll do a little better here in WA overall in terms of power. 

[Woodchuck]

6.0's are good engines, the lighter duty trans is not a real highpoint but it is what it is. Do this, hook a 6.0 truck to your trailer and pull a big hill. Then go hook it to a Duramax and pull the same hill. The difference is startling.
The Duramax takes the least amount of oil of all the diesels. Injectors are a known possible issue at least in the older ones, they are fired by multiplied oil pressure. It has been suggest by many that regular oil changes seem to really lower the rate of failure in the the Duramax and Powerstroke. The Allison trans can not be beat in the light truck auto trans world. The mileage gains alone help offset some of the higher maint. costs for a truck that will last a great deal longer. 

[MHWASH]

While Woodchuck makes a good point on the diesel, not everyone needs one. I could not justify spending the 5-6k when I only toy 10 -12 times a year. I had a '04 2500 w/ the 6.0, and now have a '09 6.0. They both do a fine job, but not in the same class as a diesel. If you can step up to the newer tranny like I have in the '09. It is a 6 speed and  I like it alot better than the 5spd auto. Both rigs got the same mileage, 12 average, 14 hwy, and 9 towing. Being a gas motor I'm very happy with the PU. I tried to find a 8.1, but they were just not around.

[HntnFsh]

Ya,I was seriously kicking around a diesel. And would love to have 1. But with the amt of towing i will be doing,the price difference in fuel and maintenance. I just cant justify the added costs. Around here gas has been dropping significantly. But diesel is still really high.45-75 cents a gallon more. I wouldnt use the diesel in a way that would come close to offsetting the costs involved.

 I have been seeing a few 8.1s with the Allison. And they seem to run a little cheaper than the 6.0. From what I have been hearing they get about 10 mpg no matter what. I may consider that option. It might just come down to which 1 I can get a better deal on. Wish I could step up to an 09 but I'm going to have to stay around 20 grand.

Think I will start getting the Tundra detailed and ready to sell.Then start some serious shopping.

[rasbo]

i own one and tow a 23ft komfort,9 mpg ...11mpg towing my 17ft alumaweld..15 to 17 mph depending on terrain with the truck alone...I use tow mode and gear down on climbs and take it easy

[Masterhunter340]

I have 01 6 liter with 170,000 miles and it tows my boat with camper or my stick trailer great. I even added the computer chip and it gives it even more power!