Jump to content

PLEASE HELP!!!! TUNE HELP

bholden

By bholden
in Modifications & Accessories

Recommended Posts

bholden Enthusiast

bholden

Posted
Posted

Hey everybody.... I need some help or some guidance. I have a 2015 GMC Sierra SLT Z71. I am fed up with the way this thing is shifting. Fed up to the point i'm just ready to count my loses and just trade the damn thing in. When i am driving and i pull away from a red light it acts like it hesitates shifting from 2nd to 3rd gear and i'm feeling like i have to damn near push the paddle to the floor in order to get it to shift from 2nd to 3rd. And then don't get me started on when i have to make a 15-20 mph turn and then get get back on the gas.... then it really goes crazy...its like its surging and hesitating all at the same time. I took it to my local dealer a couple of times to have them check it out and of course they say "We cant find anything wrong with it. Its not throwing any codes. Its probably the characteristics of the type if tranny you have or its the active fuel management system." I love the truck but i cant get pass the way it shifts. Has anyone out there had an issue like i am having and if so have you had luck with tunes. As far as changing shift points and all that good stuff.......PLEASE HELP.

WhineyTTwins Enthusiast

WhineyTTwins

Posted
Posted

There is a service bulletin for a software upgrade regarding this. Also, if your rear end is the 3.08, it's always shifting around. Had my software updated almost every time I go to the dealer. They can usually do a full reset and then upgrade again and it goes away for a bit. The car seems to adapt and go back to old ways though but nowhere near as bad as it was before the first update was released.

Ryan698 Enthusiast

Ryan698

Posted
Posted

I put a Diablo tuner on mine and never looked back I'm happy with it

 

Sent from my SM-G930W8 using Tapatalk

Rkaroll953 Enthusiast

Rkaroll953

Posted
Posted

i hear ya i hate the shifting also. get the range amf to keep it from goin to v4 cuz that is half the battle. the gas pedal flexes also i shoved half a paint stick behind it. other than that tune it if you dont mind voiding the warranty.

victorsdaddy Enthusiast

victorsdaddy

Posted
Posted

I hate the downhill braking. I drive downhill to work, and I like to just coast down. But with my Sierra it starts braking even though I don't need to

 

Sent from my Nexus 6P using Tapatalk

ricker6869 Enthusiast

ricker6869

Posted
Posted

BlackBear has all these tranny shenanigans sorted out in their tunes. It will feel like a whole new truck. Will feel like you just added 100HP with the proper shifting.

bholden Enthusiast

bholden

Posted
  • Author
Posted

BlackBear has all these tranny shenanigans sorted out in their tunes. It will feel like a whole new truck. Will feel like you just added 100HP with the proper shifting.

I heard about black bear ....but I'm concerned about it maybe running to rich ...and possibly burning out the catalytic converter...I've heard ppl complain about that ...that's what I'm worried about.

 

 

Sent from my iPhone using Tapatalk

bholden Enthusiast

bholden

Posted
  • Author
Posted

There is a service bulletin for a software upgrade regarding this. Also, if your rear end is the 3.08, it's always shifting around. Had my software updated almost every time I go to the dealer. They can usually do a full reset and then upgrade again and it goes away for a bit. The car seems to adapt and go back to old ways though but nowhere near as bad as it was before the first update was released.

yes I have 3.08 gears ...

 

 

Sent from my iPhone using Tapatalk

WhineyTTwins Enthusiast

WhineyTTwins

Posted
Posted

yes I have 3.08 gears ...

 

Sent from my iPhone using Tapatalk

 

Then yea, that's a factor. From what I have heard (NEVER PROVEN MYSELF), the diablo helped deal with some of the transmission shift points on the 3.08 rear end. Maybe someone else can chime in but I remember that before I bought the truck, I researched the forums and was told to stay away from the 3.08, especially if I am towing because it is always shifting around due to the gears being so long.

bholden Enthusiast

bholden

Posted
  • Author
Posted

 

Then yea, that's a factor. From what I have heard (NEVER PROVEN MYSELF), the diablo helped deal with some of the transmission shift points on the 3.08 rear end. Maybe someone else can chime in but I remember that before I bought the truck, I researched the forums and was told to stay away from the 3.08, especially if I am towing because it is always shifting around due to the gears being so long.

yea I never towed anything...and I have no need to as of now. The shifting was so annoying I had a set of 26s on it (33.2) tall I took them off in hopes it would help the shifting and It really didn't help at all.

 

 

Sent from my iPhone using Tapatalk

bholden Enthusiast

bholden

Posted
  • Author
Posted

I ordered my diablo last night and can tell you my thoughts on it in a couple weeks

Thanks man, I would love to hear you thoughts on your new tune!!

 

 

Sent from my iPhone using Tapatalk

WhineyTTwins Enthusiast

WhineyTTwins

Posted
Posted

yea I never towed anything...and I have no need to as of now. The shifting was so annoying I had a set of 26s on it (33.2) tall I took them off in hopes it would help the shifting and It really didn't help at all.

 

 

Sent from my iPhone using Tapatalk

Nah, It may have helped it by being SLIGHTLY less sluggish but the 3.08 has terrible shift points. I have the 3.42 but I know the symptoms you are talking about because mine does the same thing just not as bad. Call a dealer (other than your normal dealer) and say you want to see about taking your truck in. Give them the VIN and ask if there are any software updates for the car. That would be a start.

 

bholden Enthusiast

bholden

Posted
  • Author
Posted

So you think my problem maybe more deeply rooted then just the factory programming...considering I have 3.08 gears

 

 

Sent from my iPhone using Tapatalk

ricker6869 Enthusiast

ricker6869

Posted
Posted

I heard about black bear ....but I'm concerned about it maybe running to rich ...and possibly burning out the catalytic converter...I've heard ppl complain about that ...that's what I'm worried about.

 

 

Sent from my iPhone using Tapatalk

I've been tuned for about 17k miles on my 2014 with out issues. In reality just a TCM tune will fix the shifting issues from factory. These trucks have a separate computer for the engine (ECM) and transmission (TCM) the TCM tune will fix the torque management issues that cause the "clunky" shifting from factory.

FYI: At 3k miles I was really disappointed with my truck...really had no confidence in passing on highway...could not predict if it would downshift or not :M16: . I was told that Blackbear could fix this with tuning and bit the bullet. I was freaked out when Justin from BBear downloaded a modded TCM tune...it was like driving a sports car....truck just shifted gear after gear...exhaust note when shifting sounds like my stick shift LSX...going quickly thru the gears. I recommend BBear because it really worked great for me...if anything look around locally for a tuner that can mod your TCM...you will be pleasantly surprised how changing Torque management setting will help your trucks driveability.

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Latest Articles

  • Posts

    • Grumpy Bear
      Grumpy Bears 2015 Silverado 2WD

      By Grumpy Bear · Posted

      Notes 7/18/2026   3,400 miles on this batch of Mobil 1 Euro 5W40 since the GDI pump replacement. Alcohol runs very clean when ring seal is tight and the sump isn't getting hosed with fuel. Checked oil level at fill up today as is my practice and grabbed a white Kleenex to look at the color. What color?  I was going to change it but.....  
    • Another JR
      2 speed transfer case optional now?

      By Another JR · Posted

      4 low is really nice on steep boat ramps. 
    • Chuck FB
      Gas Prices

      By Chuck FB · Posted

      Interesting, I suspect I would have fueled up in Lee Vining as the day prior I would have filled up either in Laughlin or near there and maybe again before I entered Death Valley and once out the other side late that evening as I kept on driving into the night up near Lee Vining. Next morning I most likely fueled up in LV before heading over Tioga Pass into ( as I refer to it as "Yose .... Mite" 😁 ). And again that was 19 years ago but the price then must not have jumped out at me like the 5 bill a gallon theme of nutty cult hippy country Big Sir or head so far up their rear Aspen. I'd be curious to know where the highest prices are in the lower 48, I probably would not be far off to guess somewhere in Cali forn ie. Coldfoot and Prudhoe bay may have those prices beat but that is a whole other world up there and when prices are more normal elsewhere that is about what they can be up there I believe in no mans land. Anyway interesting that the 395 corridor is hosing people and the thing is, its tourist season and its not like there are a lot of competition options when driving up that highway from what I could see. Yup, big ole Boaterhomes and various other RV's ahead and behind me at the Yosemite entrance gate and they have to get their fuel somewhere.  
    • Atlas
      Gas Prices

      By Atlas · Posted

      Those can be high, as well as the big California cities. The ones that will pop your eyes out are the 395 corridor on the Eastern side of the Sierra Nevadas. Lee Vining, $7.19 for regular and $8.89 for diesel is what the Google said right now.
    • newdude
      2020 Trailboss 6.2 replacement

      By newdude · Posted

      Correct.  2019-2021 model years are serviced by a different p/n.  19420611.  Recall 2021s use 19420611.   The recall engines 2022-2024 model years are serviced with 12740076.     The difference between 19420611 and 12740076 is GM changed injector size for 2022.  The injectors are smaller on 12740076 with smaller injector bores in the cylinder heads to match the smaller injectors.  So you can't install a 19420611 in a 2022-2024, and you can't install a 12740076 in a 2019-2021.     Both engines are the replacement engine p/ns that are in the L87 recall.  So both of these are the updated engines.     Here's a version of the L87 recall with the p/ns for all the parts needed.    RCRIT-25V274-7075.pdf   Note it shows 19420611 and 12740076 with an asterisk to a footnote "Use the VIN and the GM Electronic Parts Catalog (EPC) to determine which part to order if two or more part numbers are listed for the same part, as it may vary by vehicle options."    

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...