2017 silverado stumble/jerking

[sickofmychevy]

Trying to figure out my 2017 silverado 1/2 ton with the 5.3. Has been to dealer with no fix. When you get to the bottom of a hill and start to incline around 1500-1800 rpms truck starts to do a slight jerking motion. Dealer said it was torque converter, had one installed and still doing it. Trans fluid and plugs changed still has problem. Any suggestions? To me it feels like a misfire. No lights on dash. Dealer now says that normal. Almost to the point of trading it in for a ford(not really).

[rav3]

Here's my take on it, as I have a '17 Silverado with the 5.3L V8 & 6L80 6 speed transmission with approx 47k miles. Mine kind of does the same thing but that is subjective, as I'm not driving your truck. Mine may be totally different. Anyway, I think that its the torque converter slipping at lock-up. I've watched a ton of Youtube videos on this. IIRC, the torque converter has a clutch material on the Lockup device (drum for lack of knowing the correct name). The control module is programed to Lock up the TC at low speeds (as someone commented). The pressure isn't high enough to keep it locked into the Lock -Up mode, and it will engage & disengage, depending on several factors and give you that "jerky" feeling. This is all done to achieve more MPG; i.e. Higher transmission temperatures to make the fluid thinner, early Lock-up, and coupled with the engine going from V8 to V4. I also read that the GM TC clutch material is a type of carbon fiber, to allow for these conditions.

The high thermostat temperature on the transmission is the biggest reason the TC fail and the resulting effect is the shrapnel destroys the transmission.  With all that said, I'm wondering if something like " Shutter FIXX" additive would help this or not. Basically, it has a friction modifier in it to help the clutch from slipping. I heard that adding this to the 8 speed transmission fixed it's shutter issue, where GM just changed to a different M1 ATF for the fix.

I have done the pill flip, 3-4 drain & fills on the tranny, added a Range V4 delete and added Lube Gard. Mine runs much lower temp, smooth shifts but I still have a slight shuttle when it's lugging. Once it down shifts, it's fine.

Let hear your thoughts guys. 

 

[16LT4]

Lubegard, and in some cased their additional Shudder fix, works wonders on GM transmissions, or any older transmission.  I run a bottle in every automatic transmission I own.

 

Misfires are easy enough to see on live data on a scan tool; all engines can misfire to varying degrees without tripping a CEL or registering a DTC, some have a higher threshold than others.  This is because ALL engines misfire.

 

Without scantool and diagnostic data, everything will just be a guess.

[rav3]

48 minutes ago, 16LT4 said:

Lubegard, and in some cased their additional Shudder fix, works wonders on GM transmissions, or any older transmission.  I run a bottle in every automatic transmission I own.

 

Misfires are easy enough to see on live data on a scan tool; all engines can misfire to varying degrees without tripping a CEL or registering a DTC, some have a higher threshold than others.  This is because ALL engines misfire.

 

Without scantool and diagnostic data, everything will just be a guess.

@16LT4....Have you actually put the Lubegard FIXX additive in your tranny? Any negative or positive comments?

[diyer2]

This problem has been posted a lot. Why not switch the trans fluid to 100% synthetic. Worth a try to me. 

[rav3]

@diyer2....if I'm not mistaken, most all Dexron 6 is full synthetic fluid. However, on ALL fluids, heat & wear, wears out the modifiers in ALL fluids. Heat is the biggest killer on Torque converters, when they come apart they will then grenade your transmission. Lower transmission temperatures, replace fluids & possibly add better additives. 

[diyer2]

Full synthetic is not 100% synthetic. Amsoil or Redline would be.

[rav3]

1 hour ago, diyer2 said:

Full synthetic is not 100% synthetic. Amsoil or Redline would be.

 

....

Edited February 10, 2023 by rav3

[16LT4]

On 2/10/2023 at 11:52 AM, rav3 said:

@16LT4....Have you actually put the Lubegard FIXX additive in your tranny? Any negative or positive comments?

Yes. I only post from personal experience. 
 

My 6L80 has a bottle of Lubegard and a tube of shudder fixx in it, and drives/shifts as smooth as can be with 107k miles on it. No rapid TC lock/unlock, no Chuggle, no lazy shifts, no shifting confusion. I drove it 190 miles one-way today and trans temps never got higher than 144*F. Fluid is either AC Delco or Valvoline Dex 6 (I forget what I have in it right now). 
 

My original 1986 2004-r is also living nicely behind the 350 in my car too, with a bottle of LG. I put in a bottle on every transmission I service, every time. 

Edited February 12, 2023 by 16LT4

[rav3]

1 minute ago, 16LT4 said:

Yes. I only post from personal experience. 
 

My 6L80 has a bottle of Lubegard and a tube of shudder fixx in it, and drives/shifts as smooth as can be with 107k miles on it. No lock/unlock, no Chuggle, no lazy shifts, no shifting confusion. I drove it 190 miles one-way today and trans temps never got higher than 144*F. Fluid is either AC Delco or Valvoline Dex 6 (I forget what I have in it right now). 
 

My original 1986 2004-r is also living nicely behind the 350 in my car too, with a bottle of LG. I put in a bottle on every transmission I service, every time. 

Thanks for that info. I too use the Lubegard in my 6L80, replace pan fluid about every 10k miles & did tge pill flip to keep the fluid cooler. Even driving in the mountains of WNC, the temperature is much like yours. I just added 2 Oz of the friction additive FIXX & will see how it does.

[krdeal]

I have the exact same problem after a new transmission and torque converter on my 2014 1/2 ton. I believe it's the MAF sensor. In my case the issue is in top gear only at part throttle going uphill.

[rav3]

11 minutes ago, krdeal said:

I have the exact same problem after a new transmission and torque converter on my 2014 1/2 ton. I believe it's the MAF sensor. In my case the issue is in top gear only at part throttle going uphill.

Yep....kind of sounds like mine. I think the FIXX has made mine better. You'd have a code if MAF was bad 

[It's Tim]

On 2/9/2023 at 11:09 PM, sickofmychevy said:

Dealer said it was torque converter, had one installed and still doing it. 

If the torque converter was trashed it probably took out the pump as well... transmission should have been taken care of at the same time.

[rlcole321]

For "sickofmychevy" if your still monitoring this, see if it does it when you shift it manually, if it does, then it's probably a runnability issue.