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PLEASE HELP!!!! TUNE HELP


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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.

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.

Posted

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

 

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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.

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

 

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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.

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.

 

 

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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 ...

 

 

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Posted

yes I have 3.08 gears ...

 

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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.

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.

 

 

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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!!

 

 

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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.

 

 

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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.

 

Posted

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

 

 

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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.

 

 

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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.

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