TJay74

I don't want to go Bilstien since the truck is brand new and has the AT package with the Rancho shocks, would rather stay with Rancho.

Changing the rear shocks would be ideal, but Rancho does not have the specs yet for the OEM shocks they are making for GM and they don't have an option yet. Only way to try and find something is to get the mounting types, and then the shock measurements and see if they have something that will work. Otherwise I may have to upgrade to the 5000 series which is their adjustable shock.

So I had my local shop put on a rear shackle kit to lower the rear of my truck down 2" and level it out. Truck looked great and around town seemed to ride fine. The truck is a 2014 Sierra crew cab with the All Terrain package (factory Rancho shocks). While driving on our trip this weekend and hitting some decent bumps and dips in the road it has now become apparent that since the truck is now 2" lower that the shock is blowing thru it travel due to being lower in the shock valving. I called Rancho this morning and they confirmed this, they also said they are not sure if they will offer any options for a shock that needs to be 2" lower in the shock travel until after 1st quarter of 2014. They suggested lifting the front as the better option (plus they were pushing their quicklift front kit which comes ready to go out of box and replaces the front strut assembly) or my other option will be to get the front spacer lift kit and go that route. Only other option it to get the stock rear shock mounting styles, the compressed and extended measurements and see if Rancho can come up with a shock that will work on the rear. Right now they don't have the full specs on this shock yet from their OE side. Now I am on the fence, I hate to lift the front as it will look stupid since I have zero intentions of ever running a larger tire.

If you do the shackles and blocks you will be dropping more than the 2" the shackles provide. I did nothing to the bump stops.

Shackles only, I mentioned the blocks to my buddy whos shop did and he said to only do the shackles. The block looks to be 1.5-2 thick. If you do the shackles it will take 1-2 hours, you have to drop the rear hitch assembly to get the shackle bolts out from what the shop told me. I don't mind the slight rake, looks way better than the stock look. I wont ever run a larger tire so that is why I went this way over the front lift kit (moves the lower shock mounts up 2" instead), plus then you have to get a front end alignment as well. If you do the rear you will need to take at least 2 360° turns out of the front headlight adjusters to get them down some. It is super easy and that is a estimate, even with 2 turns out the lights are still up a bit from the factory setting(which I think is too low, I am sure it is low incase of weight in the bed which then levels the lights out).

Some of it is the truck, while inside the truck it is quite do to the engineering that went into the sound, it sounds a little better from outside but still not a loud enough growl for me....yet. After Christmas I will be going down and having the resonator cut off with a straight pipe in its place. Also I can tell you the stock muffler is very restrictive. That backpressure valve even when open takes up a lot of room. The is a half dollar round weight on the back of the valve that when the valve is open sticks up about 1/2" into the exhaust stream. There is also a mesh grate with filler that covers the inlet pipe before the exhaust goes into the muffler, all of that leads to restriction.

Don't let the after fool you, the street in front of my house is on a slight incline and the sun was to the left of the truck, it sits level now with 6.25" from top of tire to bottom of fender on both ends.

I do, here is mine with the belltech rear 2" drop shackle kit on my 2014 All Terrain. Before and after.... before after

I just had a Magnaflow 5x11x22 put on mine today. It is deeper at idle and a little deeper at speed, but not as much as I wanted. If it doesn't change over the coming weeks we are going to cut the after muffler resonator off and go from there.

I seriously doubt it is the calibration or that GM detuned the calibration. It would be very easy to find that out, have someone with HPT scan the calibration and then we can compare it to another stock calibration and see if they are the same or not. I don't see how you guys are getting such bad mileage, I have the 6.2 and am averaging over 15mpg and that is with the truck barely getting into V4 mode and with only 600 miles on the truck.

As of a couple of years ago GM no longer makes the vehicles 49 state emissions certified, they are now 50 state certified (for California). The last cat in that picture is a cat, it is a unmonitored cat so it can be cut out of the system and wont affect the running of the truck at all since it is not monitored. When GM added them to the 2009 G8 cars the pup cat caused a 5hp change in the rating, so I would assume prob close to that on the truck as well. If my muffler shows up today at the shop I am going in after work today to have mine done. Currently am going with a Magnaflow 5x11x22 3.5" in/out - center/offset muffler for mine. It is the only muffler that Magnaflow offers that is 3.5" in/out which is what the 6.2 trucks are using now. I will let you all know how it sounds once I get it done, if it doesn't add enough sound in I may have the shop cut out the last resonator and go from there.

It does take several thousand miles for the engine to break in completely, until then the mileage will be done some.

At the rate the V4/AFM engages on my truck it wont do crap for the gas mileage. If it was not for me wanting to lose my warranty I would have tuned it out already. Maybe once HPT figures a way around the flash counter I will tune the AFM out and then make some adjustments to the transmission calibration and some of the non-fueling stuff on the engine side.

Still having issues with mine as well, clean and clear and they go off randomly at times.

Has anyone else had issues with the sensors once the white stuff hit the ground. My sensors are clear of any slush or snow on them or the bumper, but they are constantly going off then the DIC says the sensors have been turned off. Are they error'ing out due to maybe the signal bouncing off of the snow covered ground? Anyone else have this issue?

The computer calculate mpg will always be off, it is basing it off of the fueling calculation that runs the fuel injectors. Hand calculations is the only way to be accurate.

I hand calculated my new AT with the 6.2 motor this morning. I had 110 miles on the tank, DIC showed 17.9mpg and hand calculation was 15.01mpg. I am not worrying about mpg until the motor gets 3000-5000 miles on it. Either way still better than the 2010 5.3/AT this truck replaced and a lot more power/fun factor as well.

I would do that before I bought the sesors and harness, you are just thorwing money into the issue at this point and running blind.

I would use AC Delco sensors, make sure to clean out the sensor chamber and once you put the new ones in RTV the rubber boots down so moisture does not get in and corrode the sensors again.

being that is a safety feature I seriously doubt it is stored with the seat memory system.

They are really hard to find, I wanted a 6.2 in the AT edition and the dealer had one but was really low balling me on the my trade. I didnt have to have the truck so I walked. Then I found the 5.3 AT I have now. Love the truck, but yes wish I had the 6.2 motor.