Torque converter shudder continues

Pearl2017 · January 28, 2019

I'm not buying the hygroscopic bit. when up to temperature the fluid will get hot enough for any moisture to vaporize and leave the same way it entered. And mine started the chuggle @~25k miles and a few weeks after returning from a 5500 mile trip towing a huge trailer. The trans would go over 200 degrees at times and i live in dry hot Arizona with almost no moisture to condense in the trans..

I don't believe the chuggle is causing permanent damage. The reason is that the issue itself is a clutch that is having trouble maintaining a consistent slippage %. So it is meant to be slipping and it is modulating between too much and too little that is all ...it just gets "Grabby" not really destructive.

slipping the clutch smooth and consistently is not as easy as it sounds. The grab point is at one pressure and the slip point is at another. The computer has to control the clutch actuator between these two points without you feeling it. The properties of the fluid are being adjusted to hopefully address some sort of breakdown in the fluid. So an increase in Viscosity and maybe a bigger dose of friction modifier? I figure the fluid may just last longer than before to get GM out of the warranty period.

NomadicCPO · January 28, 2019

6 hours ago, Pearl2017 said:

I'm not buying the hygroscopic bit. when up to temperature the fluid will get hot enough for any moisture to vaporize and leave the same way it entered. And mine started the chuggle @~25k miles and a few weeks after returning from a 5500 mile trip towing a huge trailer. The trans would go over 200 degrees at times and i live in dry hot Arizona with almost no moisture to condense in the trans..

I don't believe the chuggle is causing permanent damage. The reason is that the issue itself is a clutch that is having trouble maintaining a consistent slippage %. So it is meant to be slipping and it is modulating between too much and too little that is all ...it just gets "Grabby" not really destructive.

slipping the clutch smooth and consistently is not as easy as it sounds. The grab point is at one pressure and the slip point is at another. The computer has to control the clutch actuator between these two points without you feeling it. The properties of the fluid are being adjusted to hopefully address some sort of breakdown in the fluid. So an increase in Viscosity and maybe a bigger dose of friction modifier? I figure the fluid may just last longer than before to get GM out of the warranty period.

I completely agree with you on your points except the “hot enough to vaporize moisture” comment. I live in a humid climate, and even towing right up to my safe weight limits have never seen the fluid get above 190. Most of the time on the highway it sits in the 170-180 range...well below the boiling point of water.

You’re probably right though...kick the can down the road far enough to get it past the warranty.

GPHusker · January 29, 2019

I had my 2018 in this past week for the shudder issue. They stated the new machine wasn't available but they noted they flushed and added new fluid with blue label. I felt the shudder once or twice on the way home and since then its gone. I guess we will see what happens next.

HondaHawkGT · March 18, 2019

On 1/28/2019 at 2:33 AM, Pearl2017 said:

I'm not buying the hygroscopic bit. when up to temperature the fluid will get hot enough for any moisture to vaporize and leave the same way it entered. And mine started the chuggle @~25k miles and a few weeks after returning from a 5500 mile trip towing a huge trailer. The trans would go over 200 degrees at times and i live in dry hot Arizona with almost no moisture to condense in the trans..

I don't believe the chuggle is causing permanent damage. The reason is that the issue itself is a clutch that is having trouble maintaining a consistent slippage %. So it is meant to be slipping and it is modulating between too much and too little that is all ...it just gets "Grabby" not really destructive.

slipping the clutch smooth and consistently is not as easy as it sounds. The grab point is at one pressure and the slip point is at another. The computer has to control the clutch actuator between these two points without you feeling it. The properties of the fluid are being adjusted to hopefully address some sort of breakdown in the fluid. So an increase in Viscosity and maybe a bigger dose of friction modifier? I figure the fluid may just last longer than before to get GM out of the warranty period.

Transmissions don't get hot enough to drive off moisture completely. Especially since the trans fluid goes through a cooler before returning to the pan. Even then, some of the moisture will remain inside the case and be reabsorbed. It's the same reason why brake fluid degrades over time, eventually corroding the brake lines from the inside out, as well as lowering the boiling point of the brake fluid.

Just because you live in a region with low relative humidity doesn't mean the fluid can't pull moisture from the air via the case vent. It might take longer than somebody living in Washington state, but it will still happen.

Z45 · March 18, 2019

Once the ATF is contaminated with moisture it is compromised and no longer performing like it should. The problem is the design of the fluid that let the moisture attack and weaken the ATF.

samckitt · March 18, 2019

Anyone heard any news on some new fix that is supposed to come this month (March '19)? I had mine in last month & they changed the fluid again, (its had fluid changed, new torque converter, & another fluid change in 6 months) and it worked great for about 200 miles. Then back to the same crap, this time I think it is worse. I drove it about 100 miles round trip on interstate last weekend & it was TERRIBLE. Could feel what felt like a missfire surge/shake pretty much constant. Not a super hard shaking, but could definitely feel it. Drove me nuts!

Yustinaaron · May 3, 2019

On 3/18/2019 at 7:01 AM, samckitt said:

Anyone heard any news on some new fix that is supposed to come this month (March '19)? I had mine in last month & they changed the fluid again, (its had fluid changed, new torque converter, & another fluid change in 6 months) and it worked great for about 200 miles. Then back to the same crap, this time I think it is worse. I drove it about 100 miles round trip on interstate last weekend & it was TERRIBLE. Could feel what felt like a missfire surge/shake pretty much constant. Not a super hard shaking, but could definitely feel it. Drove me nuts!

What's the cost on the torque converter change? I've got issues with 2014 Z71

midwestdenaliguy · May 7, 2019

On 5/2/2019 at 10:03 PM, Yustinaaron said:

What's the cost on the torque converter change? I've got issues with 2014 Z71

According to the dealer invoice I received when they did this last week, parts (new TC and updated fluid) and labor (doing triple flush cleaning, installing new TC, and reprogramming Tranny with updated software) was $1900. GM covered it.

Dearmosd · May 8, 2019

what exactly is the symptoms?

Yustinaaron · May 15, 2019

After having the symptoms of bad torque converter and stalling tranny, I traded in the 14 Z71 last week on a 19 LT. The new whip is a lot smoother than the old one

LynS76 · May 30, 2019

Just picked up my 18 GMC with the 6.0L last week from the dealer after taking it in for the trans shudder issue. What the service advisor and tech could not answer is whether the metal shavings damaged anything else in the transmission that may cause problems down the road, or lead to premature failure. Data from the tech is below:

Problem: Check for hesitating from lower speeds. Smooths out once at highway speeds.

8465050 Oil Pump Replacement

Verified customer concern trans has a hesitation while trying to accelerate. Verified fluid level is set to specs and removed fluid for a sample. Found heavy fine metal debris in trans fluid. Removed trans and disassembled trans to point of failure. Found trans pump was cored causing low pressure and damage to the torque converter.

Disassembled trans and found no other damage to trans. Cleaned all internal parts and case free from all metal debris in trans. Reassembled trans, replacing damaged parts an installing new seals and filter to trans. Flushed cooler lines and installed trans. Topped off fluid and test drove truck. Trans operating as designed at this time.

OLH for cleaning all internal parts and case reform all metal debris in trans and case.

Parts:

24245962            Converter
24248031            Housing
24248573            Cover kit
24248570            Rotor Pkg
24236933            Filter kit

Assuming the problem doesn’t reappear, how long would you all run the GM fluid before swapping it out with something better like Amsoil? And does anyone know what OLH stands for on the repair order above?

bbenavitz · September 5, 2019

2018 Colorado ZR2, 3.6 V6, 8 speed auto. At 2,000 miles from new I got "shudder" at any speed over 40 mph when the torque converter locks and the dealer installed a new converter that was a different lot number that was supposed to solve the problem. It did for 9,500 miles and then shudder reappeared. Back to the dealer yesterday and it took 4 weeks to get in because their designated technicians were back logged with all the other 8 speed auto chevys (silverado, corvette, colorado) with the same problem. The new fix is a flush and change of the tranny fluid with some new viscosity fluid. Will see.