Transmission fix finally for 14-15 sierra silverado! WOOOOT!

rocknfire · September 4, 2015

Tighten your leaf spring u bolts.

ember1205 · September 4, 2015

Sorry, it's not just "get to 6th," it's hesitation, confusion, clunking, and flair shifting. It's unbelievable how horrible these things shift. Unless GM can get them to shift like the old trucks, then I'll never buy another new one.

And what do you think causes all of that? All the truck wants to do is get to sixth. The logic that tells it how to shift has that as its goal, and it causes all kinds of goofy things to happen along the way.

Newell33 · September 4, 2015

And what do you think causes all of that? All the truck wants to do is get to sixth. The logic that tells it how to shift has that as its goal, and it causes all kinds of goofy things to happen along the way.

My 2011 wanted to get to 6th too, it's the flawed logic that's the difference....

mjj · September 4, 2015

It's ALWAYS learning. If your habits change, it learns that. It's not like the first 200 miles it's driven is what's set in stone for life.

This has had me wondering for awhile now. So what if you have a tune, could this learning process eventually de-tune itself?

ember1205 · September 5, 2015

This has had me wondering for awhile now. So what if you have a tune, could this learning process eventually de-tune itself?

Don't know... Does the tune effectively overwrite that piece of programming? Or code things in a way so as to not employ anything it has "learned"?

No Tyme · September 11, 2015

Does the tune effectively overwrite that piece of programming? Or code things in a way so as to not employ anything it has "learned"?

This is a very good question. Maybe we can get JennaBear to weight in on this!!!

Jordan18 · September 11, 2015

It's ALWAYS learning. If your habits change, it learns that. It's not like the first 200 miles it's driven is what's set in stone for life.

Night and day after I have towed a trailer vs couple hours on the highway empty.

Day after I've towed it's snappy as hell.

f8l vnm · September 12, 2015

My buddies 08 Sierra w/5.3 shifted like a dream. It had 140k before he sold it last year. Butter shifts. No clunking either.

No bucking , no flaring , no confusion just a straight shot to a certain rpm and bam a nice clean soft shift. It drives normal

My 14 is being bought back by gm , so I'm holding out hope they fixed the confused and clunky rear/leaf spring issues on the 16

It just doesn't make sense that they release trucks like with this awful computer tune. They drive these right ?

Kerrslight · September 12, 2015

My buddies 08 Sierra w/5.3 shifted like a dream. It had 140k before he sold it last year. Butter shifts. No clunking either.

No bucking , no flaring , no confusion just a straight shot to a certain rpm and bam a nice clean soft shift. It drives normal

My 14 is being bought back by gm , so I'm holding out hope they fixed the confused and clunky rear/leaf spring issues on the 16

It just doesn't make sense that they release trucks like with this awful computer tune. They drive these right ?

Every truck is going to have its issues. No matter whether it's brand new, used, new model, etc. With these trucks it's the transmission, leaf springs, vibration, etc. I would be willing to bet the 2016 models have either reoccurring issues or new issues of their own.

Newell33 · September 12, 2015

My buddies 08 Sierra w/5.3 shifted like a dream. It had 140k before he sold it last year. Butter shifts. No clunking either.

No bucking , no flaring , no confusion just a straight shot to a certain rpm and bam a nice clean soft shift. It drives normal

My 14 is being bought back by gm , so I'm holding out hope they fixed the confused and clunky rear/leaf spring issues on the 16

It just doesn't make sense that they release trucks like with this awful computer tune. They drive these right ?

It's funny. I started commuting about 12 miles to work recently. My fiancé has an '02 Grand Am GT in beautiful condition that she rarely drives, so I started driving that to work instead of my Silverado. It's amazing how nice it is to have a vehicle that responds appropriately to throttle input, and where the transmission does its job and works without confusion. I never thought I'd say this about a Grand Am vs my Silverado, but with the Grand Am I actually enjoy driving again. I think it's time for me to do something different.

jimlem · September 13, 2015

The ability to use a particular octane-rated fuel is governed by compression temperature and whether or not it crosses a threshhold to where it will cause pre-det. Modern engine design uses a significant amount of aluminum and advanced cooling systems, keeping internal motor temps down. A properly designed motor that can dissipate heat very efficiently can easily use a compression ratio of 11:1 or higher and still run on 87 octane.

There is absolutely NO WAY that GM would rate the motor for 87 if it was going to cause pre-det as that causes motor damage and GM would be on the hook for it.

You're about correct. It will run fine on 87, better on 93, better still on Ethanol. What you guys are forgetting is these engines are direct injection. They can run at 11:1 all day on any of the above fuels. Gone are the days when gas and air were brought in together via a carb. and you had to worry if the fuel would begin to combust prior to the spark plug's ignition. Now AFTER the air is compressed by the piston, the PCM decides when to directly inject the fuel (what ever the octane) a split second before the spark plug fires. So for the most part there is no pre-ignition because the fuel is injected cold directly to the combustion chamber, just a mSec before the plug fires. There really is no worry about octane anymore.

ember1205 · September 13, 2015

You're about correct. It will run fine on 87, better on 93, better still on Ethanol. What you guys are forgetting is these engines are direct injection. They can run at 11:1 all day on any of the above fuels. Gone are the days when gas and air were brought in together via a carb. and you had to worry if the fuel would begin to combust prior to the spark plug's ignition. Now AFTER the air is compressed by the piston, the PCM decides when to directly inject the fuel (what ever the octane) a split second before the spark plug fires. So for the most part there is no pre-ignition because the fuel is injected cold directly to the combustion chamber, just a mSec before the plug fires. There really is no worry about octane anymore.

GM disagrees with you.

https://www.youtube.com/watch?v=qd90yHlmfS4

The fuel is "Direct Injected" into the cylinder, but it is done PRIOR to the compression stroke. They show an animation at 25 seconds into the video demonstrating this.

Given that the fuel is present DURING the compression stroke, octane "matters" just as much as it always did.

No Tyme · September 15, 2015

All I got above was a blank spot... Was there suppose to be a video?

ember1205 · September 15, 2015

Yep.

Try putting this into your browser address bar: www.youtube.com/watch?v=qd90yHlmfS4

Bandit33x · September 29, 2015

Night and day after I have towed a trailer vs couple hours on the highway empty.

Day after I've towed it's snappy as hell.

I agree! It seems to drive way better for a couple days after I tow. But I don't know if that's really the transmission learning something or just the different feel of not having 5,000 lbs dragging behind you. It's probably just psychological.