Towing at CGWR with current 6.0 gasser

[bickford]

GM's current 6.0 gasser is rated for a Gross Combination Weight Rating of 18,500 with the 4.10 rear end. At 340 HP and 380 ft-lbs of torque behind a 6 speed automatic, there should be MUCH better performance than an old-school 6.0 equipped truck.

I'm considering buying a new truck with this engine and plan to tow a 5th wheel travel trailer which would add up to almost the 18,500 GCWR. Upgrading to the diesel adds $8,395 to the MSRP without a great mileage improvement (for the 2009 LMM Duramax).

Do you have similar towing experience with a late-model GM 6.0 and this transmission that you can share?

Thanks!
Joel

[bickford]

I just found the following AMAZINGLY GOOD article that tests modern trucks for heavy towing:

http://www.pickuptrucks.com/html/2007/shootout/hdshootout5mpg.html

It looks like the 6.0 will do fine for my application.

[Mark Rinker]

This 6.0L will do fine with that kind of weight.

However, you'll probably spend more on fuel, if it performs like my 2004 K3500 6.0L gasser did. Maybe there have been improvements in that department, not sure.

As for acceleration, performance in hills, grade braking, etc. there isn't alot of comparison. Diesels are made to tow.

However, the cost savings of the gasser over diesel is compelling...any way you could test drive both with a similar load in tow? Something off the bumper, perhaps?

[bickford]

However, you'll probably spend more on fuel, if it performs like my 2004 K3500 6.0L gasser did. Maybe there have been improvements in that department, not sure.


The article quoted above lists the 6 speed automatic as having a sixth gear ratio of 0.67. This should keep the rev's down and help the highway mileage compared to your 2004 (when not towing).

[Mark Rinker]

Makes sense.

Also, the only purpose for our gasser was towing or snowplowing, no other use.

Too bad the diesel upgrade has gotten so expensive. Have you looked into the effect on resale? I don't know the answer to that - haven't watched gasser prices, but I know used Duramax trucks are going cheap.

[Quack_Addict]

The only experience of value I came away with from my 2002 6.0L gasser / 4L80E truck was that I will never own another for towing applications.

The HP / torque numbers of the 'new' 6.0 are more impressive than the LQ4 (or whatever it was) in my truck - but to get to the HP/tq numbers they advertise, you're spinning some serious RPM's to get there.

I will never forget pulling my 23' boat up some moderate hills at 55mph, the 6.0L truck downshifting into 2nd gear for about 2/3 of the hill climb, bouncing the engine off the rev limiter and still decelerating the whole time. My 6.0 L truck was also completely guttless for acceleration on a level grade with the boat in tow. Fuel economy was about 12-13mpg unloaded and down around 7mpg pulling.

My current truck with the LBZ Duramax (crew cab / long box, same as the 6.0L HD I had) averages 19-20mpg unloaded. Pulling the same boat it averages 12.3mpg and the Diesel has no problem with the hills that the 6.0L struggled on.

If you are going to spend the money on a new truck, the Diesel power package isn't that much more (in the grand scheme of things) and it adds to the resale value after you're done with it.

All I can say is my 6.0L gasser left me feeling like I showed up to a gun fight carrying a pocket knife. Food for thought.