Sir Dan

You can't just turn it on. The computers decide when it wants to turn it on. Sorry. You can always just use manual mode and down shift.

There must be tow/haul grade braking and regular grade braking then because mine kicks in outside of tow haul mode also.

Check out this thread. 6 and 8 speeds are different also I believe.

HDC is different and separate from grade braking. HDC uses vehicle brakes and grade braking uses the transmission.

Grade braking is active by default. You hold in the tow haul button for like 5 seconds to toggle it on/off. It is then reset to on with every key cycle. The owners manual is great for things like this you know....

If you ever fill your tank with "topping off the tank" or "fill to spill" as you put it, there is a real chance that you caused the problem with your evap canister/system. You are supposed to stop filling the tank when it clicks off to allow room in the tank for the evap system to function properly. No doing so risks overloading it with liquid fuel.

If the truck had been sitting for days before your test drive, it could just be tire flat spotting. Take the truck for an extended test drive and if still shaking after tire balance. Run, don't walk from the truck.

Sounds like it's just a GM 8 speed doing GM 8 speed things. Horrible transmission in my opinion.

I had a hypertech tuner 10 years ago and had issues with it. They were a horrible company then and still are it seems. These new rolling computers we call trucks are getting near impossible to do any aftermarket mods to, but something like setting the speedo for tires should be a no brainer for the dealership and they should take full responsibility for the whole mess.

^^^This^^^ There is a known issue with the HP fuel pump leaking into the engine oil.

If your looking at the lights on the buttons to see if they come on during remote start mode, you won't see any indicator light even though they are on. This is normal. Also, when it's very cold and no one seated in them, these new seat heaters don't do much more than take the chill off. My 2001 truck would roast your ass if set to high.

Would the engineers actually design something like this? Seems unlikely...

I can confirm. Sounds pretty normal for the ever horrible 8 speed. Especially if you're still under 10,000 mi on it. If it's below freezing out, I've learned to just put in drive and sit for 30 seconds before moving. Seems to help a lot.

Sounds like you should have purchased an SUV or a camper top if you want a completely dry cargo area. All the bed covers will leak to some degree.

I just hate reading about issues like this. The mobile computers they have turned these trucks into are making them nearly impossible to use. Nice and cushy but one little computer glitch and you're done.