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2013 Avalanche "Grade Braking" question to new owners ...

U

utahpablo

Full Member
Joined
Oct 6, 2011
Messages
220
Hello all, my wife & I took a short 600 mile trip ( all scenic 55 byway ) to break in our new 2013 Avalanche 2wd and we hadn't felt the new 6 speed " Grade Brake" until we were heading down a 5% grade  and Wow, thought the tranny was locking up! :eek: yes it slowed us down that much! So I had my wife ( who was driving at the time ) tap the gas and it came off and back to life. Has any other 2013 owners been "Surprised" with this feature, Now that I re-read the owners manual I'm fine with it, so now I can disengage it when I need to as I'm light on the brakes anyway, ( manual says the Grade brake uses the engine and trans to brake the truck ) but Wow, our 2003 Z66 with tow mode never did this before. It's funny now, but if we had a few folks tailgatin' us as usual we might have made some new close friends...
 
My father and I were cross-country road-tripping in my new 2013 Av this past fall, and the first time the grade braking kicked in it surprised the heck out of us as well (and I was definitely a bit nervous hoping something wasn't wrong!)!
 
Yes, it really kicks in hard, thought the tranny was dropped into low at 45 mph! easy to disable though, now that I re-read the manual, just hold the end of the trailer mode button in for three seconds after starting the engine, it will tell you it's off on the DIC. It will stay off until you turn off then restart the engine ( recycle )
 
Just out of curiosity, since these are "learning" transmissions,"  think the harshness of the braking will tend to smooth-out, over time?

Nick
 
I would hope so Nick, but Wow :eek:.... it will surprise you the first time! I can always just tap the gas to release the "Grade Brake" if I do forget it's on..
 
I dunno.....

When a transmission causes a vehicle to behave in an unexpected manner, it sounds like a safety hazard to me.  

Regardless of how many times an owner's manual tries to warn us of these changes, I think it still sounds a little dangerous - especially if a younger driver happens to be behind the wheel.

So far, most everything I've read about the 6-speed makes me wonder whether the extra 1/2 mile per gallon was worth it.

By the time I trade in my '08 (last model year for the 4-speed,) much more should be known about how to civilize (tune) the 6-speed.

Until then, I'll be tracking your observations with great interest.  I'm making a list, and will be checking it twice.

Pretty sure someone like Justin @ BlackBear will be able to answer my questions & concerns.

I appreciate all the help & guidance I get from the club members.  Probably don't mention this often enough.

Nick
 
Nick@Night said:
I dunno.....

When a transmission causes a vehicle to behave in an unexpected manner, it sounds like a safety hazard to me.  

Regardless of how many times an owner's manual tries to warn us of these changes, I think it still sounds a little dangerous - especially if a younger driver happens to be behind the wheel.


Nick
Click to expand...
That reminds me of when someone asked me about anti-lock brakes, he was saying they could cause accidents because people stop breaking when they feel the vibration in the pedal they didn't expect. I told him that when you get a vehicle with them each driver of the vehicle should find an empty wide road and make sure to activate the anti-lock brakes in the rain a couple times so they knew what to expect.
 
And anti-lock brakes haven't saved my ass since two days ago. Running in tight, merging 80 mph traffic when accident up ahead brought all to an immediate halt. My bad for being that close....only excuse was jockeying during the high speed merge. Ex race car driver but no way I'd have made it through without the tech and good tires.
 
I recall warming up to anti-lock brakes, almost immediately.  Not sure what the connection is to grade braking, though.  

Sounds like some of you have experienced the grade braking, and are cool with  it.  I haven't, with my humble 4-speed. Just trying to agree with utahpablo, who seemed to be saying it detracted from the driving experience.

Can't even imagine how it would be with speed control engaged.  Again, that's because I haven't  experienced it.  Pretty sure I'm not going to like it, though.  

In fact, note to self:  Have Justin @ BlackBear make grade-braking the very first thing he tunes out of my first 6-speed.

Nick

 
Yes Nick, as said before, it will feel like you shifted from overdrive into low in a "snap", going down a steep grade, it will wake you up......but by just tapping the gas, the trans & engine go back to normal.......... until the next steep downgrade
 
This is mere speculation on my part; but, I think I could live with this feature if the default state was "off."  That way, I could experiment with it, then leave it off permanently if it made the driving experience less enjoyable.

I know that is probably asking a lot, these days.  We're pretty much stuck with what they gives us, which opens up a money-making opportunity for the tuners.

Thanks for responding, guys.

Nick
 
Nick@Night said:
I recall warming up to anti-lock brakes, almost immediately.  Not sure what the connection is to grade braking, though.  


Nick
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They are both safety features that can be surprising/unexpected if you have never experienced them.

The grade braking is a safety feature that helps prevents brake fade especially while towing a trailer.
 
We always called that downshifting. Something you did as required. I view it more as a convenience feature. Only a safety thingy wrt preventing appliance operators from hurting themselves or others. Honda's had this in their auto trannys since 1998, although back then it was mild/less intrusive. They call it grade logic. Towing....that be what that tow/haul switch has long been there for.
 
ltxi said:
Honda's had this in their auto trannys since 1998, although back then it was mild/less intrusive.
Click to expand...

Mild & less intrusive sounds better to me. 

Anyway, the 6-speed grade braking sounds like it would be  great for towing, hauling, & for negotiating mountains.

Almost can't wait to try it out myself, but plan to drive my '08 for a few more years.  Thanks for schooling me.

So far, I have identified 4 personal technical hot buttons for the GMT-900 platform:

(1) AFM
(2) Heated washer fluid module
(3) Generation 9 OnStar (minimum requirement for RemoteLink)
(4) Grade braking

The first two, I can correct, now.  The other 2 can only be experienced or corrected, once I trade up.  Even then, it won't be for one of those elusive Bermuda Blues, will it?

Nick
 
ltxi said:
We always called that downshifting. Something you did as required. I view it more as a convenience feature. Only a safety thingy wrt preventing appliance operators from hurting themselves or others. Honda's had this in their auto trannys since 1998, although back then it was mild/less intrusive. They call it grade logic. Towing....that be what that tow/haul switch has long been there for.
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As I stated before, My last 2003 Avalanche Z66 had the tow / haul switch that I did use all the time, and yes it did down shift a gear when applied, that is not the issue here, when the 6 speed tranny goes into "Grade Brake Mode" it really SLAMS the trans/engine into low gear, something that will make you think the truck is broke at first as it hits that hard, too damn hard for my taste. So I'm disabling it, just wanted to give a heads up to other folks like myself who may not know about this "great feature". Saving brake pads? my 2003 Z66 went 120,000 miles on the stock pads and still looked great ( with 70% pad left ) when I sold it, and I drove the hell out of hills up and down
 
My experience is that mechanical systems are always trying to tell me something.

They tell when they're happy.  They tell me when they're sad.

When a transmission sounds & feels like it's close to breaking (while braking,) it probably is.

Nick

 
I am so over GM. Have been for a long while. My last/last new GM car was a '78 Cutlass. Been doing Chevy 4x4s since '75, but after my Y2K Silvy with brakes from the little shop of horrors and other less frightening stuff the only thing that kept me in house for trucks was that no one else makes an Av.

My 2008 has been free of anything major so far....just relatively trivial, annoying crap.....but expecting to and having to remap the engine and transmission management right out of the box to get it to run right?? That's simply not cool.
 
Well, it's been a few months of driving from my last post here and the new 2013's 6 speed tranny's learning curve must have "Graduated" as the tranny brake has been super smooth no matter how steep the hill may be, but yes those first few hundred miles were a real eye opener :eek: while it was going to "school"...
 
I loved the brake feature when towing with my Tahoe. I pulled a u-haul through the mountains and the grade braking saved some hot brakes on those roads. I also noticed that it did learn and smooth out. At first the downshift was a bit jarring. I also felt it was a little unpredictable as to when it would happen. After a few hundred miles with it, the system seemed to learn how I was driving and adapt to it. The shifting became smoother and I could tell when it was going to come on. Ever pulled a trailer up a really steep slope with the cruise control on? When you get to the top of the hill you suddenly find yourself accelerating too much and you end up braking. This system helps to minimize this. It was pretty cool. Once again though, it takes time for the system to learn what you are doing.
 
As I read the 2012/13 manuals that came with the trucks....the default for the "jake brake" feature is OFF..the grade braking feature is only turned on and active when the trailer button is pushed on the end of the shift stalk.

I go down 15 degree grades in normal mode and it doesn't kick in.


I like the 6 speed over the previous 4 speed.....real smooth......and I don't miss the 2-3 upshift clunk.
 
Page 9-32 of the 2013 owners manual.

Normal Mode Grade Braking
Normal Mode Grade Braking is
enabled when the vehicle is started,
but is not enabled in Range
Selection Mode. It assists in
maintaining desired vehicle speeds
when driving on downhill grades by
using the engine and transmission
to slow the vehicle. The first time
the system engages for each
ignition key cycle, a DIC message
will be displayed. See Transmission
Messages on page 5‑42.
To disable or enable Normal Mode
Grade Braking within the current
ignition key cycle, press and
hold the Tow/Haul button for
three seconds. A DIC message
displays. See Transmission
Messages on page 5‑42.
For other forms of grade braking,
see Tow/Haul Mode on page 9‑33
and Cruise Control on page 9‑47.
Click to expand...
 
Started in normal mode and tried the 15 degree grade today in trailer mode and it kicked into braking mode just fine, not exactly smooth but not too abrupt either,....... you could feel the downshift and rpm rise (probably more abruptly if a trailer was attached).....enable/disable through the trailer button.

Sufficient braking without a trailer attached, but if towing, I'd rather use the integrated trailer controller braking system, where the rate of trailer braking is configurable and has a manual override, which interfaces to coordinate trailer braking with the vehicles antilock brake and stability control systems.



 
At the very least, it's beginning to sound like the 6-speed is something I can live with, when the time comes.

What I don't understand is why an '11 Avy seemed so doggy when I took it for a test drive, last November?

I understand the concept of "learning" drive-train components.  What I don't understand is why a particular truck chooses a different curve, when accelerating from a standing stop.

From a standing stop, why should the experience be so much more pleasing when Bob is behind the wheel, rather than Nick?

Thanks for listening.
 
Of course the 6 speed will shift quicker and more often, but transmissions aside the '12 and '13 appear to have the same  pep as the '07.....might be the number of miles on the engines or gear ratios....new engine doesn't seem to get too gutsy until after the first 2K or so....difference was most pronounced traveling  up a long 15 degree grade....engine let you know it didn't like to rev. above 3K or upshift past 3rd. .....had to baby it in the slow lane for the first 1K. Difficult to be too objective the '07 had a 3.73 rear and besides the 6 speed, the later ones a 3.42.
 
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