David89GMC

Stay away from the 6.5TD for towing. That engine was optimized for fuel mileage, not power. You can build that engine up to respectable power and longevity, for lots of money. The 6.0LS is designed for occasional towing, as it's a gas engine. And it's bulletproof if not abused. Sounds like your mind is made up on a dually, so get the 2008. But that's only my opinion. I've got an '03 K2500HD SRW, CC, with a 6.0LS that is rated to tow 9000 pounds.

Get a one year subscription to AllData for your year and model of truck. Everything is there.

Why would an oil leak cause the engine to knock? You won't like the 5.3 if you ever try to tow anything. Just how can you justify the expense? How many YEARS of ga$ $aving$ will the 5.3 $$$wap have over just keeping the 8.1? That's an expensive swap. If you're able to swap the 8.1 for a 5.3 and handle the technical issues, why can't you just coax more fuel mileage from the 8.1? A smaller engine will have to work harder than a large engine, so the 5.3 mileage won't be nearly what you expect. Get a good programmer and adjust the parameters until your 8.1 mileage gets better.

Strongly suggest you get an ALLDATA subscription. From what I see, the dash needs to be removed. Look for a BLK/WHT on pin C5 of the Instrument Panel relay block Ground Bus. It's also connected to the Traction Control Switch BLK/WHT wire and the Multifunction Accessory Switch BLK/WHT wire. Good luck.

https://treperformance.com/i-23900950-gm-vortec-trucks-suvs-2001-2002-6-0l-v8-vortech-supercharger-v-2-sci-complete-kit.html https://www.summitracing.com/parts/vor-4gx218-150l/make/chevrolet Sorry to say this, but if you aren't able to convert from cable to wire, are you able to take on adding a supercharger? The 6.0 makes plenty of power to tow up to the maximum rated towing of your truck.

You need to completely rebuild that rear end. The ring gear's looking worn and you have pieces laying in the bottom of the case. Luckily, the 14 bolt is one of the easiest integral center sections to rebuild. If you're a mechanic, this should be straight forward and inexpensive. Or, just get a good used one from a boneyard, there are millions of these trucks on the road.

Is your 2007 a "classic"? In other words, is your truck a GMT800 or GMT900? If it's not a "classic", the beds for 2007 to 2014 are the same. "New body style" normally refers to a GMT800. To verify the fit, find the 2006 and 2008 Body Builder's Manuals and compare them.

Bad gas? If so, the computer might adapt and the shuttering may stop.

Get the 2000 GMT800 Body Builder's Manual. It should be available online and tell you if it was a factory option. I can say they don't show a CCSB 1 ton dooley in the 2002 BBM.

Look online for the pdf of the "Body Builder's Manual" for your model and year. It should be a GMT800. Sorry, but it's too big to upload.

Why did you put 2011 parts in a 2002 vehicle? Did you replace everything in the power steering and hydroboost 2002 with 2011 parts? Newer doesn't mean upgrade, it most likely means incorrect. Even in 2002 there are several different power steering pumps, with different connections. I did my '03 2500HD and had to learn this before ordering a new pump. Hate to say it, but get the correct parts for your vehicle and try again. Or ask Blue Top to help with the problem. Even their website shows very different steering gear models between the "2011 upgrade" and your model year.

Good information from CamGTP, the 6.0 is what we used to call "detuned". Just getting a hotter tune may be all you need. Keep in mind that the LY6 has variable valve timing, so you might look more closely at modifications for that.

My crew cab is a real blessing. There's a huge amount of space in the rear area when the seats are folded down. I have two large dogs, so I got a large piece of carpet from Home Depot that goes from the front headrests to the rear window and they're happy as can be. For a work truck, either rear seat can be folded and valuables stored there. The crew cab short bed (6.5 ft, CCSB) is actually longer than a standard cab long bed (SCLB). This makes the CCSB a great platform for towing, my '03 CCSB 2500HS 6.0 4x4 has a gooseneck hitch in the bed.

An AllData subscription would be a good start. eTrailer might be a good source as well.

Why do you want to do this? I see the advantages of the gmt900 over the gmt800, but it's not at all practical. See CamGTPs response. For example: If you have a wrecked 2014 with a good drivetrain, get another GMT900 with a bad drivetrain and put the two together.

Google is just not trustworthy. CamGTP showed you the owner's manual data, so go with that. I have an '03 GMC 2500HD 6.0 4l80e and wouldn't consider towing more than 8000 lbs. My trailer is 7000 lbs fully loaded and the truck bed is full of stuff. The truck labors a bit, even in Tow mode, but at least I'm safely within the truck and trailer's limits. You need a 1 ton diesel duelly to pull that 15K trailer safely. Sell what you have and get a used 24 valve Dodge duelly.

Of course the harnesses could be the problem. Get the correct harnesses. Thanks for typing out the problem. Nobody opens unknown attachments anymore.

DVD players need to be connected to ground in order to play when the engine is running. That toggle switch might have been used to enable a DVD video to play while driving. Other than that, there's no way for us to know what the previous owner thought they were doing.

Wow, 5mpg? Could the brakes on your trailer be sticking? Or is the brake controller not working correctly? Are you using Towing Mode? If so, you've probably noticed the increased rpm before shifts, and harder shifts. The higher rpm will reduce mileage. Does your 2500 have a 4L80E or the 4L60E? BTW: my '03 K2500HD 6.0 4L80E 4.10 gets about 10 mpg empty.

Most "cold air intake" setups put the filter on a short hose to the throttle body. This ain't good. Unless you isolate the filter from the engine bay, you're just installing a Hot Air Intake.

Did you clean the tires of all debris and check them for roundness? I often get what you describe and it's always a rock stuck in the tread, front or rear. Radial ply tires can fail with this symptom. A clunk on each revolution indicates a wheel or axle related problem. The propeller shaft turns 4 times the speed of the wheels and final drive, so you can disregard that as a source. Since this is a dually, I'd suspect the rear differential. After 16 years of towing and hauling it's not unusual for the rear end to go bad.

Check out the online ALLDATA manuals. There are $15 per year deals, but the basic subscription is $20. I found it to be far better than Chiltons, and it's model-specific. So, you can get a 2006 GMC 3500 manual and see the differences before spending the big bucks for the set of paper or DVD manuals.

Cleaning the connectors to the throttle body worked for me.

Your truck has Hydroboost power brakes. When the power steering pump gets up to pressure the brake pedal will tend to move upward, but not "violently". My guess is dirty fluid or a partially plugged line. The steering box could also be responsible for this pedal behavior. This is a safety issue, so have a good mechanic take a look at it.

The 6.0 LQ4 is a torque engine, unlike the 6.0 LQ9 which is the same engine designed for higher rpm in Cadillacs and a couple other platforms. My '03 GMC 2500HD LQ4 CCSB was used for towing vehicles with a gooseneck hitch and car trailer before I got it, and the engine is still in great shape. Although the 4L80E was burned up, so I had it rebuilt stock in case something goes wrong on the road. The 8.1 has an Allison transmission behind it and is more powerful and better for towing than the 6.0/4L80E. I looked for an 8.1/Allison for quite some time, and found a few, but they cost at least 75% more that the 6.0/4L80E. So I got what I now have for $4000 and am very happy with it. My 7500 pound travel trailer is noticeable behind my GMC but I'm not at all concerned about it with the tow mode shift points and efi changes. After all, it's not a diesel dually meant for full-time towing. I can unhitch and have a very nice 4x4 truck to play with or just drive into town. Good luck with your decision and new to you truck!