re: Silverado/Sierra downshift/engine braking?

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When I am traveling at low speeds and then let off the accelerator, instead of a smooth coast, I get a jerking set of downshifting and what feels like engine braking? Almost feels the way a standard would if you just coasted into a stop in gear.

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I have a 2015 Silverado and mine does something similar. When I'm travelling at lower speeds (stop and go street driving) I can feel the gears shift and a jerking sensation at times. Not smooth at all. Had a 2006 Silverado prior and never had this problem.

I brought it to the dealership last week and they kept it for 2 days. They did about a million tests on it (supposedly) and test drove it 3 times. They couldn't find anything wrong with it or have it do what I was telling them it did.

Now I am seeing some people in this thread say it's just the way these trucks run now. Not sure what to believe, but other than that the truck runs fine. Just a minor annoyance.

Yeah, I meant "haven't" it was a typo.

I haven't noticed the tach either. I'll look later today.

Do you have the 5.3L?

2015 Sierra Z71 here, same issues with the rough shifting.

Did some more searching. This dude described exactly what i am feeling:

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I hate how the trans downshifts ( talking about only 30 mph or below) It's like a manual trans with the downshifting. Truck just doesn't "free roll" near as much as my old truck. I even turn off the grade braking.. doesn't seem to change anything.

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From that thread:

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From GM:
"What you are probably feeling with your coasting downshifts is that we are leaving the torque converter applied during the shifts. We do this because if the trans is backdriving the engine, the engine can reduce the amount of fuel the engine is getting to make fuel economy better. The shifts should get a bit better in feel with miles, but will probably not get to the same feel (or lack of feel) that an older truck [4-speed] may have had."

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we are putting fuel economy over comfort at ridiculous levels.

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You have hit the nail on the head.
Its very aggervating

That's not surprising.

I'd like to see GM's estimation of how much fuel that will save over the lifespan of a typical pickup truck.

Your transmission may have an aftermarket tune on it.

I had a lifter collapse on a DOD cylinder (displacement-on-demand, aka 4 cylinder mode) a few weeks ago. I had about a quarter inch gap between the top of the pushrod and the rocker arm. When I replaced all the lifters on the left side, I got the engine and transmission tuned to turn off the DOD and to tighten up the shifts. I don't mind the tighter shifts because I hated the mushy feeling but it can be annoying in bumper to bumper traffic when it lunges.

My truck is a 2010 Yukon Denali with 101k miles for what it's worth. Besides the displacement and the cam, they are essentially the same Chevy LS motor with the 6L80 transmission.

My guess is that it's your transmission tune.

Ah. Didn't realize you meant it was a new gen GM truck. I haven't done much driving on those to feel the difference but I do know they shift differently.

I rescind my statement.