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Jarneson

6 speed having same issues as 8 speed

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Has anyone on here had the same issues with there 6 speeds as the 8 do? I brought my 2018 Chevy 1500 in to the shop and first they told me the U bolt were really loose causing my truck to slip and clunk on take off and slowing down as it shifts! So once I got it back it still did it so once again made another app to get it looked at and they said it normal for my truck to shift and down shift hard! Well sometimes it feels like someone rear ending me it’s so bad! Just curious if 6 speeds have the same issue as 8’s do? 

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Does anyone know how to turn off the v4 so it’s just 8 I think that would help?!?!?

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If you put the truck in L, it will only use gears 1-5 and no v4, 8 cyl only.  Give it a try. 

 

I have a 2018 5.3 /6 speed and don't have those issues.  Sometimes a small to moderate downshift clunk that went away when I went from stock 31.5" tires to 33", oddly.  At 3500 miles now. 

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Posted (edited)

I have a 5.3L with the 6 speed, all stock. I think it’s the grade braking that causes the hard downshifting when coming to a stop.

 

I’ve played around a bit with mine and this is what I’ve found. First off, the clunk isn’t always there, maybe only 5 - 10% of the time. The 2 - 1 clunk is always worse when the engine is in V8 mode. It’s much less noticeable when slowing down in V4 mode. Yesterday I turned off grade braking for the first time (hold down the tow/haul button for 5 seconds) and it was super smooth when coming to a stop. I could see the transmission shifts on the tach, but I couldn’t feel them.

 

Like others have always said, I think it’s just the way these trucks are programmed to shift. The adaptive learning transmission has helped some. Mine has gotten less rough in the 7,000 miles I’ve had it. It’s night and day difference from when it was new! 

Edited by BriDroid

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9 hours ago, Jarneson said:

Does anyone know how to turn off the v4 so it’s just 8 I think that would help?!?!?

 

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Posted (edited)
10 hours ago, Jarneson said:

Has anyone on here had the same issues with there 6 speeds as the 8 do? I brought my 2018 Chevy 1500 in to the shop and first they told me the U bolt were really loose causing my truck to slip and clunk on take off and slowing down as it shifts! So once I got it back it still did it so once again made another app to get it looked at and they said it normal for my truck to shift and down shift hard! Well sometimes it feels like someone rear ending me it’s so bad! Just curious if 6 speeds have the same issue as 8’s do? 

 

8 speed has some odd shifting at times.  Some normal, some not.  Some 8 speeds encounter torque converter shudder, which if you drove one that does it, you'd know exactly what it felt (and sounds) like. 

 

Otherwise, two totally different transmissions.  6 speed may flare on 2-3 shift after driving it once, shutting it off, then restarting the truck.  That is normal.  Once and a while, some minor fishbite.  Harsh downshifts seem to be grade braking related. 

Edited by newdude
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My 2018 6 speed has had clunks, delayed shifts, doesn't hold onto gears as long as I'd think, hunts, fish bites...since new. 30,000 miles later and it's still the same. I've driven others and they all feel the same to me. I've changed the fluid once already, no change. Some people sorry about AFM failure, I worry about transmission failure, but maybe I have nothing o worry about? I guess time will tell.

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Mine would have bump downshift from time to time. I think a lot of it is due to GM keeping the torque converter clutch locked up more often. They're trying to keep it locked as often as possible so the truck basically engine breaks and reduces the amount of gas the truck is burning. Ram and Ford also use these technique and get similar complaints when it's noticeable.

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My WOT shifts are really rough too! Feels almost like the transmission is going to fall out sometimes. 

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Hypertech MaxEnergy 2, disable AFM. Set trans to Sport. Throttle to Track.

 

 

 

 

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Thanks guys for the input! I have 10k on mine and it started at 2k somedays it worse then others but most of the time it feels like it’s gonna fall out it knocks so hard I feel like! I noticed my pin seal is leaking on my rear end now and also when I shake my truck the supports for leak springs and grinding, might be Lose so once again it’s going back in! 

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has anyone tried installing the software from the previous model trucks into the trans puter?  I have a 2012 sierra with the same tranny , and man it shifts sooooo much better than the newer 2016 silverado with the same trans.. 

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