Nearly Died Last Night!

Silverado Steve · June 16, 2015

Problem is, you don't have time to even think of that process, let alone execute it, in the sort of scenario the OP described.

I'm going to have to disagree with your statement. The OP mashed the pedal and the ECM didn't process that to downshift more than it did, had the OP released for a second and re-mashed the pedal, the transmission would of dropped another gear or two. I have that issue every time I merge onto I-25 here in Colorado. The issue here is there is no sizeable speedup lane to merge onto the highway and every on ramp seems to be a loop with a speed limit of 35 mph. The speed here is 75 mph on the stretch of highway I drive everyday and there are plenty of semi's cruising the right lane at 80 mph or cars passing in the right lane going 90. Instinctually, to get up to speed I always double mash my gas pedal... since at 35-45, my truck likes to loaf in 5th gear around 1,500 rpm, mashing the pedal once, it will drop to 4th maybe 3rd then jump back up to 4th or 5th. When I double mash it drops down to 3rd right away and the RPM's jump up to 5,500 RPM's and will hold the gear as long as I have the pedal down. However, I'm sometimes foiled by the driver who never attempts to get up to speed merging on the highway. Of all the places I've lived, Colorado Springs may have the worst collection of drivers in the US. We have people who completely stop on the merge lane waiting for an opening and will enter the freeway going 40 mph when traffic is light.

ember1205 · June 16, 2015

I'm going to have to disagree with your statement. The OP mashed the pedal and the ECM didn't process that to downshift more than it did, had the OP released for a second and re-mashed the pedal, the transmission would of dropped another gear or two. I have that issue every time I merge onto I-25 here in Colorado. The issue here is there is no sizeable speedup lane to merge onto the highway and every on ramp seems to be a loop with a speed limit of 35 mph. The speed here is 75 mph on the stretch of highway I drive everyday and there are plenty of semi's cruising the right lane at 80 mph or cars passing in the right lane going 90. Instinctually, to get up to speed I always double mash my gas pedal... since at 35-45, my truck likes to loaf in 5th gear around 1,500 rpm, mashing the pedal once, it will drop to 4th maybe 3rd then jump back up to 4th or 5th. When I double mash it drops down to 3rd right away and the RPM's jump up to 5,500 RPM's and will hold the gear as long as I have the pedal down. However, I'm sometimes foiled by the driver who never attempts to get up to speed merging on the highway. Of all the places I've lived, Colorado Springs may have the worst collection of drivers in the US. We have people who completely stop on the merge lane waiting for an opening and will enter the freeway going 40 mph when traffic is light.

I get what you're saying and don't discount its effectiveness. But, see it from the OP's perspective: "Double mashing" the gas pedal is not typical in everyday driving. So, when you're trying to move from essentially a stop in one lane to 60MPH in another, and there's a truck closing in on you, that "one second" you alluded to has just allowed that truck to travel 88 feet closer to you. Factor in another .25 seconds to mash the pedal in the first place and realize it isn't working, then half a second to remember "Wait! I need to let up and mash it again!", and another .25 second to mash the pedal a second time. You're now up to two full seconds of elapsed time, and 176 feet that truck has traveled while your nose is just starting to eke into his lane.

I like that the motor ALWAYS returns to 8cyl mode under about 8MPH. The motor is always ready to provide lots of power on demand. Why can't the transmission accept it and transfer it to the wheels?

I agree with the previous statement that GM isn't going to even give the issue a second thought until lawsuits start piling up showing that improper tuning of the transmission actually -causes- accidents. The reason I have only owned a couple of 4cyl vehicles in my life is because I drive a lot of highway and use the accelerator pedal to avoid accidents almost as much as the brake pedal. Not so with this truck... I've already had half my life scared out of me from a similar type of scenario and have totally changed how I approach lane changes, merges, and the like. What has me concerned is that one emergency situation that could possibly arise when the truck simply isn't going to respond to a press of the gas pedal when I need it to.

CounterMeasure · June 17, 2015

I've recently found that if I want the 8L90 in my truck to somewhat understand what is purpose of existence is, I have to routinely drive around in tow mode. By design, that mode holds the gears longer, and doesn't try to be in the OD gears at 40mph. That's the only way I can make sure that when I merge from a 40mph road to a 70mph interstate on a short entrance ramp on the way to work, I don't risk the transmission having a brainfart when it should be downshifting and getting squashed in the process.

Imcrazy · June 17, 2015

I've found that I prefer to use manual mode in situations like this I drove stick shift for 8 yrs before I got my Sierra almost all auto transmissions suck!

SouthernSilveradoGuy85 · June 17, 2015

Manual mode in these trucks isn't shifting the gears like you would with a manual though, it's just like any other auto that has a 1,2,3 on the dash where it just won't shift past the gear you choose. I haven't found a real need for manual mode, maybe if I get stuck in snow or mud, but that's about it. I haven't had any issues with the trans in my '14 in any situation.

j-ten-ner · June 17, 2015

Manual mode comes in handy on hilly roads.

Especially with the shifting pattern in the new transmissions.

It prevents the trans from jumping back and forward while going uphill.

Or driving on a road with a 60km/h speed limit. My trans would switch between 5 and 6 constantly.

And when I'm about to pass another vehicle on a two lane road I "shift down by hand" before flooring it.

so long

j-ten-ner

HondaHawkGT · June 17, 2015

Living near the bluffs of the Mississippi River valley, I've grown used to driving in manual mode all the time. When I'm in town I set it to M3 and gradually move to M4 and M5 as I get out on the highway. If I tried driving up the steep bluffs in drive with the 3.08 gears, I would have traded this truck off last year. Using manual mode has made the truck a lot easier to live with and fun to drive.

TLDR; Once you're used to manual mode it becomes natural and the truck is more responsive. A tune is the ultimate solution.

Alter Ego Trip · June 17, 2015

You guys need to go drive a Ram with the 8 spd. That is a transmission that shifts when it's supposed to and works perfectly. Going from my 8spd Hemi to a 6spd 5.3 was a real disappointment. That Hemi would run circles around the Chevy and is always in the right gear. I also got better mileage out of a 400+ horse motor than the pathetic 350ish horse I'm driving now.

Pretty sad when Chevy used to be the horsepower king. Now it seems like they've conceded to taking a back seat to everyone else. Chevy has so much potential but they just can't figure out how to implement it.

Jordan18 · June 17, 2015

You guys need to go drive a Ram with the 8 spd. That is a transmission that shifts when it's supposed to and works perfectly. Going from my 8spd Hemi to a 6spd 5.3 was a real disappointment. That Hemi would run circles around the Chevy and is always in the right gear. I also got better mileage out of a 400+ horse motor than the pathetic 350ish horse I'm driving now.

Pretty sad when Chevy used to be the horsepower king. Now it seems like they've conceded to taking a back seat to everyone else. Chevy has so much potential but they just can't figure out how to implement it.

This is why they have the 6.2L... and I get better mileage than a coworkers ram and he has the 8 speed. I wish, however, that they did offer it in the LT/SLE trims, as you pay a steep premium to upgrade trim levels to get the 6.2. This is actually a huge downside compared to Ford and Ram, which offer their strong engines in lower trims. One thing to also note is I do not think the 5.7 is direct injected, which is certainly what they'll do with the ram's redesign in a year or 2, and it will probably surpass the current 6.2L in horsepower (395 currently vs 420) and be very close in torque (405 I believe currently vs 460)

I would hope they do as they did in the last generation sometime in 2016/2017 MY offer it in these trims.

Silverado Steve · June 18, 2015

Yeah, i think we can all agree that both the 6spd and new 8spd transmissions are programmed to squeeze every drop of mpgs out of the engine. It seems more and more manufacturers are watering down the shift points of their transmission programming to meet the new CAFE standards set to go i to effect in what 2017. As for our trucks, i guess ive always been realistic when having to go from a dead stop and get up to highway speed in an instant, hence why i will always double mash the pedal...its a habit at this point. As others have said the only real way around this is a custom tune, or drive in manual mode. My Tacoma with a 4.0 v6 felt more quick off the line than my Chevy, but my Chevy gets equal if not more mpgs than the Toyota....something has to give for that to happen...thanks GM and your conservative TQ management

I get what you're saying and don't discount its effectiveness. But, see it from the OP's perspective: "Double mashing" the gas pedal is not typical in everyday driving. So, when you're trying to move from essentially a stop in one lane to 60MPH in another, and there's a truck closing in on you, that "one second" you alluded to has just allowed that truck to travel 88 feet closer to you. Factor in another .25 seconds to mash the pedal in the first place and realize it isn't working, then half a second to remember "Wait! I need to let up and mash it again!", and another .25 second to mash the pedal a second time. You're now up to two full seconds of elapsed time, and 176 feet that truck has traveled while your nose is just starting to eke into his lane.

I like that the motor ALWAYS returns to 8cyl mode under about 8MPH. The motor is always ready to provide lots of power on demand. Why can't the transmission accept it and transfer it to the wheels?

I agree with the previous statement that GM isn't going to even give the issue a second thought until lawsuits start piling up showing that improper tuning of the transmission actually -causes- accidents. The reason I have only owned a couple of 4cyl vehicles in my life is because I drive a lot of highway and use the accelerator pedal to avoid accidents almost as much as the brake pedal. Not so with this truck... I've already had half my life scared out of me from a similar type of scenario and have totally changed how I approach lane changes, merges, and the like. What has me concerned is that one emergency situation that could possibly arise when the truck simply isn't going to respond to a press of the gas pedal when I need it to.

galliher_nc · June 18, 2015

You guys need to go drive a Ram with the 8 spd. That is a transmission that shifts when it's supposed to and works perfectly. Going from my 8spd Hemi to a 6spd 5.3 was a real disappointment. That Hemi would run circles around the Chevy and is always in the right gear. I also got better mileage out of a 400+ horse motor than the pathetic 350ish horse I'm driving now.

Pretty sad when Chevy used to be the horsepower king. Now it seems like they've conceded to taking a back seat to everyone else. Chevy has so much potential but they just can't figure out how to implement it.

I've driven a Ram. I'll keep my GM even with the horrible transmission tuning.

ember1205 · June 18, 2015

thanks GM and your conservative TQ management

It isn't purely a GM issue. GM has laws that they have to follow or they face penalities, fines, or lack of government money. All the manufacturers do. The reason that the mid-sized pickup trucks were pushed so hard 30 years ago was because they were considered a "truck" and got better MPGs than the full-sized ones. That raised the overall average of their "truck" segment and allowed them to meet government criteria.

The standards are getting more stringent, and the manufacturers have found ways to increase the MPG of the larger trucks. Sales have shifted to the full size again, and you've seen manufacturers like RAM (Dodge) and Ford drop the mid-size truck all together because they don't benefit from the numbers and the market is simply not as strong for them. GM is doing well in this segment because there -is- a market, albeit small, that they don't face any competition in (from a Domestic manfucaturer position).

What I think is poor is not that the transmission is so "stumbly" in the way that it's set up. Rather, GM didn't provide the operator to choose an operating mode for it. Sure, there's Tow/Haul, but that's only on some of the trucks. Yes, there's "M" mode, but that defeats the AFM (I don't see that as the root of this issue). Why not offer the D/OD that we used to have? D would provide a top-gear limit, and possibly a different set of shift points for around town type of driving.

Or, tie the shift point logic in with TPS (throttle position sensor) more accurately (or set it to default to slightly more aggressive UNLESS TPS shows mild acceleration). There's a lot of different ways that GM could have set the tuning up to provide a more robust overall experience while also still showing the government that the vehice is -capable- of achieving their MPG requirements.

Think about it this way... If my truck has to get 20MPG highway to satisfy the goverment, but I drive 75MPH in M4, does that mean that GM is responsible for all of the wasted fuel?

Newell33 · June 18, 2015

It isn't purely a GM issue. GM has laws that they have to follow or they face penalities, fines, or lack of government money. All the manufacturers do. The reason that the mid-sized pickup trucks were pushed so hard 30 years ago was because they were considered a "truck" and got better MPGs than the full-sized ones. That raised the overall average of their "truck" segment and allowed them to meet government criteria.

The standards are getting more stringent, and the manufacturers have found ways to increase the MPG of the larger trucks. Sales have shifted to the full size again, and you've seen manufacturers like RAM (Dodge) and Ford drop the mid-size truck all together because they don't benefit from the numbers and the market is simply not as strong for them. GM is doing well in this segment because there -is- a market, albeit small, that they don't face any competition in (from a Domestic manfucaturer position).

What I think is poor is not that the transmission is so "stumbly" in the way that it's set up. Rather, GM didn't provide the operator to choose an operating mode for it. Sure, there's Tow/Haul, but that's only on some of the trucks. Yes, there's "M" mode, but that defeats the AFM (I don't see that as the root of this issue). Why not offer the D/OD that we used to have? D would provide a top-gear limit, and possibly a different set of shift points for around town type of driving.

Or, tie the shift point logic in with TPS (throttle position sensor) more accurately (or set it to default to slightly more aggressive UNLESS TPS shows mild acceleration). There's a lot of different ways that GM could have set the tuning up to provide a more robust overall experience while also still showing the government that the vehice is -capable- of achieving their MPG requirements.

Think about it this way... If my truck has to get 20MPG highway to satisfy the goverment, but I drive 75MPH in M4, does that mean that GM is responsible for all of the wasted fuel?

Just think of how much fuel is wasted all across the country during those crappy flair shifts. As has been noted before, getting to the tallest gear quickly isn't necessarily the issue, it's the stumbling, flair shifting, transbrake clunking downshifts, and other inconsistencies that really bother me. GM failed miserably with the programming in my truck if their goal was optimized fuel mileage. It's poor programming, and that's the bottom line.

Alter Ego Trip · June 19, 2015

I've driven a Ram. I'll keep my GM even with the horrible transmission tuning.

To each his own but the Ram has a big edge over GM in a lot of ways (power, amentities, technology, transmission, ride, interior noise, etc). My main draw to Chevy over the years was quality. I'll take an underdog if it's reliable. That's not the case nowadays. The Chevy offers very little to boast about over the other mfg's and the quality just isn't there. I want to love my new Chevy, but they are making it really hard to do so.

I have both at my dealership so I have no bias towards one or the other. I can tell you I've had more problems in the first 200 miles of ownership with my Chevy than I had in over 30,000 miles with my last two Rams.

Blind allegiance will only get you so far.

Silverado Steve · June 19, 2015

My truck doesn't have this wandering transmission that others mention, or maybe i dont care enough to notice it? In all honesty, i dont have any perceived issues with my transmission. The only thing i notice is the lack of giddy up from my 355hp/383 lbs/tq but i can deal because i didnt buy my truck to drag race. Overall im happy averaging 17mpg around town and 23 mpgs on the hwy. The power is there, but as i mentioned before, i really have to romp it....but that is becoming the case with more and more cars. Im sure there are members of other truck manufacturer forums that complain about the same thing with their trucks.

It isn't purely a GM issue. GM has laws that they have to follow or they face penalities, fines, or lack of government money. All the manufacturers do. The reason that the mid-sized pickup trucks were pushed so hard 30 years ago was because they were considered a "truck" and got better MPGs than the full-sized ones. That raised the overall average of their "truck" segment and allowed them to meet government criteria.

The standards are getting more stringent, and the manufacturers have found ways to increase the MPG of the larger trucks. Sales have shifted to the full size again, and you've seen manufacturers like RAM (Dodge) and Ford drop the mid-size truck all together because they don't benefit from the numbers and the market is simply not as strong for them. GM is doing well in this segment because there -is- a market, albeit small, that they don't face any competition in (from a Domestic manfucaturer position).

What I think is poor is not that the transmission is so "stumbly" in the way that it's set up. Rather, GM didn't provide the operator to choose an operating mode for it. Sure, there's Tow/Haul, but that's only on some of the trucks. Yes, there's "M" mode, but that defeats the AFM (I don't see that as the root of this issue). Why not offer the D/OD that we used to have? D would provide a top-gear limit, and possibly a different set of shift points for around town type of driving.

Or, tie the shift point logic in with TPS (throttle position sensor) more accurately (or set it to default to slightly more aggressive UNLESS TPS shows mild acceleration). There's a lot of different ways that GM could have set the tuning up to provide a more robust overall experience while also still showing the government that the vehice is -capable- of achieving their MPG requirements.

Think about it this way... If my truck has to get 20MPG highway to satisfy the goverment, but I drive 75MPH in M4, does that mean that GM is responsible for all of the wasted fuel?