Yes. Trans computer will not allow any harmful shifts to occur either. Depends on the year of the 'bu also and which trans it has. My '15 2.5 'bu would give a shift denied message if it didn't like what I was trying to do.

 

I'm not sure how the computer could consider staying in the gear it is already in (6th gear) a harmful shift? I would think it would be harder on the engine and trans (though arguably not "harmful") to force the downshift from 6th to 4th. Doesn't make sense to me.

My 'Bu is a 2012 with the 2.4L. It never forced a downshift like my Terrain does when moving the shifter from D to M.

 

Manual in these isn't a true manual. It simply sets the highest gear it will shift to by itself. If you put it in manual and then select 4, the transmission will shift by itself in the range of 1-4.

 

If you put it in manual and then select 4, the transmission will shift by itself in the range of 1-4.

I do this sometimes. When its in manual the truck pulls harder than when in drive.
It feels like it has more torque. I wonder why that is?

 

Depends on what speed you notice the increased torque. It could likely be the placebo effect !

 

Downshifting the computer will not let engine rev over the set redline of the engine. It may be close to the redline but it will not let it exceed the redline.
Some of the 8 and 9 speed transmissions actually have a double overdrive. The top 2 gears are overdrives.

 

Downshifting the computer will not let engine rev over the set redline of the engine. It may be close to the redline but it will not let it exceed the redline.
Some of the 8 and 9 speed transmissions actually have a double overdrive. The top 2 gears are overdrives.

Yeah, OK ... but my (and @Theta2Drive 's) question stands: Why even do the downshift? The Computer gotten you to 6th Gear ... where it thinks it should be for the current Engine speed. But you put it in "M" and now it's not smart enough to know that nothing needs to be done (immediately)?

Maybe this is a "Safety" feature??? A way to slow the vehicle down if you've lost your Brakes?? Maybe that's what it is? If so, this should be mentioned in the Owner's Manual ... but I'd bet it isn't...

 

Why would the average driver shift from D to M when already driving in D other than to use engine braking?
Seems logical to me.
From the manual:
Manual Mode Electronic Range Select (ERS) Mode ERS or manual mode allows for the selection of the range of gear positions. Use this mode when driving downhill or towing a trailer to limit the top gear and vehicle speed. The shift position indicator within the Driver Information Center (DIC) will display a number next to the M indicating the highest available gear under manual mode and the driving conditions when manual mode was selected
When shifting to M (Manual Mode), the transmission will shift to a preset lower gear range. For this preset range, the highest gear available is displayed next to the M in the DIC. See Driver Information Center (DIC) 0 110ii for more information. All gears below that number are available to use. For example, when 4 (Fourth) is shown next to the M, 1 (First) through 4 (Fourth) gears are shifted automatically. To shift to 5 (Fifth) gear, press the + (Plus) button or shift into D (Drive). M (Manual Mode) will prevent shifting to a lower gear range if the engine speed is too high. If vehicle speed is not reduced within the time allowed, the lower gear range shift will not be completed

 

My user manual says...

"When shifting to M (Manual Mode),
the transmission will shift to a preset
lower gear range. For this preset
range, the highest gear available is
displayed next to the M in the DIC."

It is clear that GM has preset the lower gear range to 4, so when you shift from D to M the transmission downshift to the 4th gear. Same happens to my 15 Traverse, I have stop doing that. I shift to M only when the vehicle has stopped. The advantage is that the transmission will not downshift as quickly as in the D mode when slowing down at the red light. The auto mode and manual mode are two different animals, they don't in sync. Engineers!!! No ideas of their chain of thoughts.

 

Just for reference and comparison . . . our 2017 Chevrolet Colorado down shifts to 6 if "L" (ERS) driving at speed when in 8th gear (8L45 transmission) and states that it will do so in the Owners Manual. So it has the preset feature when selecting "L" when driving at speed.

In our 2019 Acadia with the 6 speed transmission and ERS, I do not recall it dropping down if shifted to the "L" position, but would have to check and see.

In wife's 2017 Chevy Sonic daily driver with the 6 speed 6T30 transmission. . . .it has a true Manual Mode ( not ERS ) that can be up or down shifted with the +/- button on the shift lever. If shifted at speed in 6th gear to "M" . .. . it remains in 6th gear, but will respond to shift commands using the +/- button.

In this car, if "M" is selected, the driver will have to remember to now shift manually because when coming to a stop it automatically down shifts to 1st gear when coming to a stop.
It's fun to use in Manual Mode, but I've used it a number of times and the engine will stay in first gear until commanded to upshift with the +/- button.

That gets a bit panicky when depressing the gas pedal and the engine will go up in RPMs quickly, waiting for the pilot driver to tell it to shift. But, it works well if wanting to optimize shift points where the little sonic engine variable intake manifold switches over to different intake runner length for optimum power. That happens at about 3,500 to 4,000 RPM and a noticeable "2nd wind" can be felt where the engine starts to pull again even more.

 

BTW, my 15 Verse downshift to 3rd gear if I shift from D to M. The false teeth could fly out of my mouth if I didn't keep my mouth shut. 😆

 

OK - I guess the way manual feature is programmed on the Terrain is different from what I am used to on my Malibu and really won't work for what I want.

To answer the question above about why would I even shift from D to M - on my commute, there are several small inclines (this is on the highway, I am going 65 - 70 mph with shifter in D and trans in 6th gear) where I would like the trans to hold 6th gear vs downshifting to 5th. The incline is just enough to induce a downshift and it doesn't really need to do that (and I prefer that it doesn't). On my Malibu, by putting the shifter in M it will hold 6th gear. Speed only drops a couple of mph and I don't have to floor it or anything like that. The engine isn't lugging. These are relatively short (in length) and slight (in gradient) inclines...like I said, just enough to induce a downshift. I'm not trying to climb a long, steep hill or anything like that.

Guess I will just have to live with a couple of downshifts to 5th on my commute...

 

I usually increase the speed (without causing a downshift) before approaching the incline. The vehicle will not downshift when on the incline.

 

That's an option too...I may start doing that as well if traffic permits.

 

Theta2drive - putting the transmission in M6 will not stop the vehicle from downshifting to 5th gear when going up a hill. In fact, as I understand it, running your vehicle in M6 makes it operate exactly like if you were operating in D mode. Your Malibu does not downshift because it is lighter, and more aerodynamic.

 

Ummm...no

My Malibu WILL downshift if left in D. Hence, why I shift it to M so it will hold 6th gear. I have had the Malibu hold 6th so long and the mph drop so far that I started to become worried about lugging the engine and manually downshifted it myself. Has ZERO to do with aerodynamics and EVERYTHING to do with the programming for M mode.

Running in M6 is NOT like running in D. At all.

 

A 2020 Terrain 1.5 SLE 9 speed drops one gear when you shift from drive to Low.

 

I guess I must have a different transmission than you. In M6, my '18 1.5l will downshift when it should. I have watched it do that by looking at the tach

If you are getting down to, let's say 15 mph, then your engine will either be lugging in 6th gear, or it has downshifted to avoid the lugging.

As I understand you, if from a stop sign, if you are in M6, it will stay in 6th gear, or am I misunderstanding you ?

Any other opinions from other forum members on their experience ?

 

The '18 model is very different from the '16, including engine and trans, so I am not surprised that they don't operate in the same way.

First, let me explain what my 2012 4 cyl Malibu does, because that is my point of reference. The computer has programmed into it various parameters about what gear is allowed at what speed, even in M mode. From a stop, M mode will allow me to start off in 1st or 2nd gear. 3rd and above are not available from a standing stop. If I am going 65 mph on the hwy, in M mode and 6th gear, steady state cruising...and I have to stop due to traffic, the trans will automatically downshift at certain speeds all the way down to first. Same situation, going 65 mph, and I encounter a hill, it will hold 6th gear down to at least 55 mph (as I recall). At that point, I feel like it is lugging the engine and I downshift it myself. I have never let the incline pull the engine down so far that it downshifts automatically, so I don't know at what speed that would happen.

OK...that is what I am used to.

In the Terrain, the first time (and everytime thereafter) I am going 65 mph, steady state cruising, and I come to an incline that will induce a downshift to 5th gear while in D, and I shift to M - the thought being that the trans would do the same thing my Malibu does, which is hold 6th gear) - it instead immediately downshifts to 4th gear. That entirely defeats the purpose of what I was trying to do.

It would appear that M mode in the Terrain is designed and programmed differently than the Malibu. From what I can discern, it is more intended for towing and or mountain driving. That's OK. Just doesn't meet my needs.

So, my options appear to be 1) leave in in D and let it downshift to 5th or 2) speed up in anticipation of the incline and allow the incline to bleed off speed without (hopefully) needing to downshift to 5th.

 

Going on 8 years with my Equinox. Have never once put it in manual mode. Have never had the need to reduce the highest gear. The Equinox shifts just fine for me going up and down hills, so aside from towing I see no need for the manual mode.

My previous car had a "real" manual mode where it would stay in whatever gear was selected. I used it in snow driving (start in 2nd gear, downshift to minimize applying the brakes, etc.) as well on occasions where I felt like manually shifting through the gears for a little fun.

 

I can tell you that in our 2008 Equinox Sport, the "Chevy" programming was to stay in the gear selected when in M mode. There was no auto-downshift when moving from D to M, it just stayed in what ever gear it was already in at the time. If you hit a steep hill and were in M6, it stayed in M6 until the RPMs dropped below a certain threshold or until you mashed the pedal to the floor. You could force/request an upshift via M mode.

In our 2015 Terrain (3.6), D to M automatically forces a downshift. M in the "GMC" programming seems to be about the highest gear the transmission will allow and will freely down/up shift as needed. Very different from how the Equinox was programmed. You cannot force/request an upshift via M mode, only a downshift.

My 2020 Volvo behaves like the "Chevy" programming. No change in gears when changing to M mode and unless RPM conflict, M mode honors the requested gear up or down.

Now why would you ever use M? Most of the time for me it is related to mountain driving. Uphill, putting it into 4 or 5 to prevent the trans from hunting for gears constantly. Just put in M4 and hold a steady speed without it shifting every 2-3 minutes up and down into 5th and 6th when it can't hold its speed on the next grade change. Downhill, putting it into 4 or 5 to hold your speed at the speed limit instead of riding your brakes all the way down. A lot of the downhills, you can put it in 5th and you stay at 65mph the entire time. Steeper grade or 55mph, use 4th. Not in the mountains?? I still do this in traffic so we aren't shifting constantly. Stop and go traffic will go 1-3 constantly even though you never made it over 10mph. Just put in in 1st and crawl, no shifts, no brakes, much smoother.

 

In both 3.6 equinox and 10 traverse, if im in D, and need to pass, i shift to L, it drops 2 gears.
Rpms go up, and gas pedal response is immediate.
Once done either manually shift to 6 or back to D.
On the traverse being in L6.
Turns off hill descent. Which keeps the computer from downshifting wheb it senses you press the brakes.
That is, on downhills, you pick up speed with the engine rpms remaining stable.
In D, you gain speed, the trans downshifts, rpms go up. Like compression braking..
5k
I dont think thats available on the equinox.
But great feature on the traverse.

 

Help me out, what does the acronym ERC stand for ?

 

Should be ERS => Electronic Range Select

 

Fixed the title - thanks for the correction.

 

The same thing happens with our '17 Equinox 3.6L AWD - it's normal.

 

Theta2drive - putting the transmission in M6 will not stop the vehicle from downshifting to 5th gear when going up a hill. In fact, as I understand it, running your vehicle in M6 makes it operate exactly like if you were operating in D mode. Your Malibu does not downshift because it is lighter, and more aerodynamic.

It's basically a lockout mode, similar to the old 123 on the older automatics we grew up with. The maximum gear allowed is the number shown. This is done to prevent overheating of the transmission when towing or during bad weather when you want more torque and less "floating down the road in super eco-mode barely connected to anything double overdrive". Everything else about it is 100% automatic - just with those upper (mostly useless) gears removed from the equation. Note - when towing, remove overdrive gears and for hills, drop it one more notch. The real danger in towing isn't "OMG - It downshifted! Extra noise and drama!" (no actual wear) but it upshifting out from under you and suddenly you are going 80 down a steep grade with zero engine braking. Most automatics will religiously like a Cardinal on Palm Sunday upshift every single chance they can get to save you that precious .00001 mpg. Wear, lugging the engine, or whatever you are hauling or towing isn't remotely a concern. Remember that 800-1200rpm is basically zero torque, which is what keeps you stuck to the road and in control.