Shudder!?

[ddann19]

Took my 2012 Yukon 6.2L with 170K to my mechanic recently for a concern I was noticing at about 60 MPH. I totally feel like one of those signs mechanics have that charge per noise or vibration it is making. But I need some help. I cannot seem to find much on here, and he couldn't get it to do what I was trying to describe. So at about or around 60 (+-3MPH) as you are accelerating there is a slight shutter, stutter, rumble, for no more than 3 seconds and then its gone and everything is back to smooth sailing. RPM will flutter a little over it, but its hard to catch it cause its so brief.

I have the diablo tune programmed, AFM shut off, ran a can of sea foam through, run 91 Octane ethanol free, All fluids(trans, diff, transfer case, brake, coolant) have been changed in last 6 months. 15K since transmission change, its been smooth shifting.

Got any leads for me to track down or places to start looking for the cause?

 

[Geotrash]

Took my 2012 Yukon 6.2L with 170K to my mechanic recently for a concern I was noticing at about 60 MPH. I totally feel like one of those signs mechanics have that charge per noise or vibration it is making. But I need some help. I cannot seem to find much on here, and he couldn't get it to do what I was trying to describe. So at about or around 60 (+-3MPH) as you are accelerating there is a slight shutter, stutter, rumble, for no more than 3 seconds and then its gone and everything is back to smooth sailing. RPM will flutter a little over it, but its hard to catch it cause its so brief.

I have the diablo tune programmed, AFM shut off, ran a can of sea foam through, run 91 Octane ethanol free, All fluids(trans, diff, transfer case, brake, coolant) have been changed in last 6 months. 15K since transmission change, its been smooth shifting.

Got any leads for me to track down or places to start looking for the cause?

Could be the lockup clutch in the torque converter. It's a weak spot in the 6L80. You're right to search for a proper diagnosis though because if it's the problem and it fails, it will take out the transmission with debris from it.

 

[ddann19]

One more thing, it doesn't do it with the cruise control active. I don't know if that makes sense or not with the clutch in the torque convertor?

 

[Geotrash]

One more thing, it doesn't do it with the cruise control active. I don't know if that makes sense or not with the clutch in the torque convertor?

Hmmm...does it feel like a misfire? Any codes being stored?

 

[ddann19]

Hmmm...does it feel like a misfire? Any codes being stored?

no codes. I tend to think you are right with the torque converter but how do i confirm or disprove?

 

[wsteele]

no codes. I tend to think you are right with the torque converter but how do i confirm or disprove?

You can do some basic tests like a stall test, etc., but frankly, I would just take it to a transmission specialist and have them perform the tests.

 

[Geotrash]

no codes. I tend to think you are right with the torque converter but how do i confirm or disprove?

Maybe someone else knows a trick, but the only way I know is to get it out and look at it. I replaced mine in my 2012 proactively with an upgraded TC that has a billet case and stronger lockup clutch assembly, at 117K, because I do a lot of towing and didn't want to have to worry about it.

I outsourced the job to a local transmission shop, and the mechanic that got my old one out said it was getting pretty worn. Total bill for the new TC and labor was around $1K.

 

[ddann19]

yeah i am thinking i just would rather upgrade myself instead of questioning it.

 

[ddann19]

Maybe someone else knows a trick, but the only way I know is to get it out and look at it. I replaced mine in my 2012 proactively with an upgraded TC that has a billet case and stronger lockup clutch assembly, at 117K, because I do a lot of towing and didn't want to have to worry about it.

I outsourced the job to a local transmission shop, and the mechanic that got my old one out said it was getting pretty worn. Total bill for the new TC and labor was around $1K.

Which TC did you go with? Rock auto has two listed....is one a HD, it looks that way.

 

[Geotrash]

Which TC did you go with? Rock auto has two listed....is one a HD, it looks that way.

The shop I worked with suggested a TC overhauled by CVC. The model is BU60-FHD. They're a remanufacturer who's apparently known for their upgrades to the stock units to make them more durable, including a heavy duty billet front, dual-plate clutch lock-up mechanism with upgraded friction materials, and a flanged hub. He likes them because he's had good experiences with their units over many years, and believes it's a quality upgrade that will support the towing I do. The unit ran about $500, shipped, which was also good, and the shop dropped the pan and changed the filter as part of the job.

Here's the thread on the job. https://www.tahoeyukonforum.com/threads/torque-converter-replace-or-let-it-be.125234/

All of that said, I welcome others to weigh in here on their choices as well. Lots of folks like Circle D, for example.