6.2L 8-Speed Transmission

[BlackZ71Silverado]

There was a post a while back made by someone who had a friend working at a dealership. They claimed to install an 'experimental' update into his TCM to fix the sloppy shifting. After reading the posts, it seems that his truck had actually been tuned and it wasn't a GM update/fix.

 

How are you guys liking the new 8-speed? Are they still not shifting properly? Any other complaints? And was there an actual GM update put out to take care of things?

 

Going to look at a few different 6.2L's this weekend, don't plan on buying but would like to know how they are working out 'just in case' I decide to bring one of these new trucks home. Looking at the Sierra Denali, a couple Sierra SLT's, Silverado High Country, and some LTZ's with the 6.2L engine.

 

What's the verdict on that combination from those of you who have owned one for a while now?

 

 

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[JRaschke11]

Mine works perfectly since day one. Zero issues. And I HAAAAAAATE it! Worst part of the truck hands down. Ordered the truck in May, took delivery on July 27. As of today I have about 4600 miles on it.

 

I have an Airaid intake tube with dry synthetic filter and Borla ATAK catback, and it often feels like I am driving a Prius. Totally gimps the truck. Hate it.

[hurricanoday]

I have 15 denali 6.2 8speed and I love it. There have been some minor (what I call minor) issues where it sometimes flares but after the update it has been good. I never had a newer 6sp but I came from an 04 Sierra Denali and the 8sp is night and day difference. It is great for driving around town and it is even better towing. Not sure what some one couldn't like about it, besides them just saying they don't like it. Has it been 100 perfect no, but it has been great. Def an improvement after the tsb/recalls gm performed. Towing my boat up the passes was awesome with 6.2 8sp combo, felt like it was always in the right gear and right rpm

 

owned mine since march and over 6k miles, got my vote for sure

[SkiDooNick700]

I've had mine since May. Over 4000 miles now. It's been great for the most part. Occasionally the 1 2 shift is really hard when Trans is cold, especially if you give it very very light throttle. I just towed with mine for the first time this past weekend and all I can say is Wow. So smooth, quiet, comfortable, and plenty of power.

[galliher_nc]

I've only had mine for 2 days/300 miles, but so far I'm liking it. The truck does still shift somewhat 'sloppily' and a good tune would clean it up, but it's nowhere near as bad as the 6 speeds I had.

[iCryWheniGoPoop]

I've had mine 2 1/2 months, 9000 miles and I feel it works as it should. It can be a little clunky at times but the latest recall (software update) fixed most of that as well. Coming from having many Allison's in the past, I feel right at home.

 

 

Sent from Off Driller Side

[Kander41]

Ordered mine and took delivery in May. 2900 miles so far and I love it. I came from a 2007 5.3 with 4 speed that had huge gaps between gears. This new 8 speed is different but mostly in the best ways. The 1-2 shift is the only gap under light throttle but smooth and unnoticeable after that. Get on it and it will hammer through gears. Towing is fanatic as others have said. Don't take a few folks negativity to draw your conclusion. They tend to post more than the positive ones.

 

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[P-Funk]

Had mine since March and have over 7k miles on it. No issues with mine at all.

[crushNchowda]

I've had a '14 w/ 5.3 and 6 speed and now a '15 w/ 6.2 and 8 speed, the combination of the throttle tip in plus the behavior/programming of the tranny actually makes the 5.3 truck feel more powerful just putting around town. Unless you really mash the pedal on the 6.2 it's tough to get it into the meat of the torque curve and with 2 more gears it's tough to drive @ 1/2 throttle and hold a gear it always wants to upshift- essentially it turns the power delivery into an on/off situation- I hate it.

 

The feeling of what seems to be the torque converter/clutch pack or whatever disengaging then abruptly re engaging when going from coasting to light throttle is maddening- feels like you're doing damage to the truck. I had a g8 gt w/ the 6L80 and it exhibited similar behavior before I had it custom tuned- once tuned it was an entirely different car- I'm sure the same can be said for the new 8 speed. I did notice after going through the adaptive "learning" process the 6L80 6 speed in my 14 truck was better than the one in my 08 G8....I'm sure the tranny software has been improved on since back in '07

 

After tuning these trannies you should be able to determine exactly how much throttle effort will result in however many gear up shifts or downshifts you are tying to achieve - on a custom tuned auto a slight upward movement from your right foot results in a 1 gear up shift...a 1/4" of travel or so back down & u get a perfectly timed downshift etc. you will be able to "feel" the shifts more as well...but not in a bad or intrusive manner.

 

I think a lot of this programming that seems annoying is done to "preserve" the tranny although it seems like it's doing damage to me and also more so to enhance gas mileage.

 

I will be getting my truck tuned in the very near future- I can attest 100% coming from a 6 speed 5.3 2014 w/ 3.42s that the 8 speed tranny in my 2015 pretty much negates the pleasure/advantage of the 6.2 engine. It's been a wash from my experience

[WendysOrBust]

I've had a '14 w/ 5.3 and 6 speed and now a '15 w/ 6.2 and 8 speed, the combination of the throttle tip in plus the behavior/programming of the tranny actually makes the 5.3 truck feel more powerful just putting around town. Unless you really mash the pedal on the 6.2 it's tough to get it into the meat of the torque curve and with 2 more gears it's tough to drive @ 1/2 throttle and hold a gear it always wants to upshift- essentially it turns the power delivery into an on/off situation- I hate it.

 

The feeling of what seems to be the torque converter/clutch pack or whatever disengaging then abruptly re engaging when going from coasting to light throttle is maddening- feels like you're doing damage to the truck. I had a g8 gt w/ the 6L80 and it exhibited similar behavior before I had it custom tuned- once tuned it was an entirely different car- I'm sure the same can be said for the new 8 speed. I did notice after going through the adaptive "learning" process the 6L80 6 speed in my 14 truck was better than the one in my 08 G8....I'm sure the tranny software has been improved on since back in '07

 

After tuning these trannies you should be able to determine exactly how much throttle effort will result in however many gear up shifts or downshifts you are tying to achieve - on a custom tuned auto a slight upward movement from your right foot results in a 1 gear up shift...a 1/4" of travel or so back down & u get a perfectly timed downshift etc. you will be able to "feel" the shifts more as well...but not in a bad or intrusive manner.

 

I think a lot of this programming that seems annoying is done to "preserve" the tranny although it seems like it's doing damage to me and also more so to enhance gas mileage.

 

I will be getting my truck tuned in the very near future- I can attest 100% coming from a 6 speed 5.3 2014 w/ 3.42s that the 8 speed tranny in my 2015 pretty much negates the pleasure/advantage of the 6.2 engine. It's been a wash from my experience

 

Wow, this is exactly how I felt when I first had my 5.3/6spd with 3.42's. Shame that some still experiencing this on the newer 6.2/8spd. I still think GM gimped these new trucks to achieve higher MPG ratings.

[fondupot]

I've had a '14 w/ 5.3 and 6 speed and now a '15 w/ 6.2 and 8 speed, the combination of the throttle tip in plus the behavior/programming of the tranny actually makes the 5.3 truck feel more powerful just putting around town. Unless you really mash the pedal on the 6.2 it's tough to get it into the meat of the torque curve and with 2 more gears it's tough to drive @ 1/2 throttle and hold a gear it always wants to upshift- essentially it turns the power delivery into an on/off situation- I hate it.

 

The feeling of what seems to be the torque converter/clutch pack or whatever disengaging then abruptly re engaging when going from coasting to light throttle is maddening- feels like you're doing damage to the truck. I had a g8 gt w/ the 6L80 and it exhibited similar behavior before I had it custom tuned- once tuned it was an entirely different car- I'm sure the same can be said for the new 8 speed. I did notice after going through the adaptive "learning" process the 6L80 6 speed in my 14 truck was better than the one in my 08 G8....I'm sure the tranny software has been improved on since back in '07

 

After tuning these trannies you should be able to determine exactly how much throttle effort will result in however many gear up shifts or downshifts you are tying to achieve - on a custom tuned auto a slight upward movement from your right foot results in a 1 gear up shift...a 1/4" of travel or so back down & u get a perfectly timed downshift etc. you will be able to "feel" the shifts more as well...but not in a bad or intrusive manner.

 

I think a lot of this programming that seems annoying is done to "preserve" the tranny although it seems like it's doing damage to me and also more so to enhance gas mileage.

 

I will be getting my truck tuned in the very near future- I can attest 100% coming from a 6 speed 5.3 2014 w/ 3.42s that the 8 speed tranny in my 2015 pretty much negates the pleasure/advantage of the 6.2 engine. It's been a wash from my experience

 

I can agree. I actually drove a 2015 6.2L 8 speed Denali on Friday. I was toying with the idea of trading up because I got a letter from my dealer saying they wanted to buy my truck. While the 2015 8 spd 6.2L 3.23 felt good. I didn't feel like it was THAT much better than my tuned 6 spd 2014 5.3L 3.42.

 

I really couldn't justify the cost of upgrading.

 

Hell, I wasn't even that impressed with the Magnetic Ride in the Denali. It was pretty good. Not outstanding like I had thought.

 

I did however also drive a 2015 2500HD with an Duramax and Alison. Also a Denali. And that truck rode phenomenal for being a 2500HD.

[f8l vnm]

well its positive to hear that the 8 Speeds dont do the flair at low speed driving like the 6 speeds do.

My 14 6.2 ( Which is being bought back by GM as we speak ) during low speed driving was just awful . It would falir up and down and then just get confused after that.

Other gripe for me was the CLUNK heard when you release the gas pedal at almost any speeds

[galliher_nc]

well its positive to hear that the 8 Speeds dont do the flair at low speed driving like the 6 speeds do.

My 14 6.2 ( Which is being bought back by GM as we speak ) during low speed driving was just awful . It would falir up and down and then just get confused after that.

Other gripe for me was the CLUNK heard when you release the gas pedal at almost any speeds

This.

 

My 6 speed trucks were really annoying to drive in stop and go traffic.

[FishinJ]

I've had mine since early July and put approx 2500 miles on it and love it so far. I don't feel the trans hunting for gears like a lot of post have said they do. Occasionally it will clunk when driving slow when you hit the gas a little, but not very often. I've towed the boat to the Keys and back (4.5 hours each way) and it was flawless and smooth. It's been the same with towing the boat locally. I've got the Denali and enjoy all the extra features it has.

[Txnolebd]

While I do think the 6.2 8 speed does rob some of the pleasure of 420hp and 460tq it definitely feels way better than every 5.3 I have ever driven. I drove several 14 and 15 5.3 trucks with 3.42 gears and you had to get down on the peddle pretty good to get the truck going. The 6.2 even with 8 speed moves with very little peddle and effort. My throttle tip in is very good and shifts are quick. I agree with those that say driving under let's say 10 mph in stop and go traffic can be a little frustrating but as soon as there is a clearing the truck moves out with no hesitation. Now I have not driven or ridden in a tuned 14 or 15 5.3 but could easily imagine it feeling comparable to the 6.2 stock.