I have an 8L45 transmission in my 4x4 pickup truck. At 6211 miles I took my truck to Stoops Dealership. They said my Torque Converter was Bad and they replaced it with another. My replacement Torque Converter went Bad at 15722 miles. They only flushed the Fluid and told me to drive 200 miles and see how the truck does. I went online and found florida and Michigan are working on a Class Action Lawsuit. I called Stoops Dealership and told them my problem is back. I want to Sell the Truck back to GMC. They said bring in the truck in and we will take a look. They wanted me to drop off truck and give me a loaner. I went with the truck and watched from the waiting area to see what went on. They had to Reps from GMC there to discuss the History of my truck.They could not find anything wrong with truck. They hooked up truck to test vibration. They did not find any?? I told Service Rep about Lawsuit, He did not know. Service rep said that both original and replacement Torque converter was not bad. I just needed the Special formula Transmission Fluid that was for this Transmission torque converter. Why did they not have this Special Transmission Fluid in truck from the start. Will changing the fluid really fix the problem. I think this will cover problem for awhile,but it will be back???
Seems this transmission was installed on many GM vehicles. Whether or not the new fluid will fix the problem, who knows. Keep all your documentation. My search showed six state so far involved in legal action. I would not expect anyone at the dealership to comment on a legal issue.
I found this on a Corvette site:
Originally posted by GM Technical Assistance Center
8 Speed Torque Converter Shudder – New Service Procedure and New Mobil 1 Synthetic LV ATF HP Fluid Regional Rollout
GM CUSTOMER CARE & AFTERSALES
URGENT - DISTRIBUTE IMMEDIATELY
| DATE | 12/12/2018 |
|---|---|
| SUBJECT | 8 Speed Torque Converter Shudder – New Service Procedure and New Mobil 1 Synthetic LV ATF HP Fluid Regional Rollout |
| MODELS | 8L45 and 8L90 Applications |
| TO | All Cadillac, Chevrolet and GMC Dealers |
| ATTN | Service Manager, Service Director, Shop Foreman, Service Technician, Parts Manager, Parts Counter Personnel, Warranty Administrator, General Manager |
A new transmission fluid exchange procedure and new formula of Mobil 1 Synthetic LV ATF HP transmission fluid is being released to address torque converter shudder on 8L45 and 8L90 applications. The procedure and new transmission fluid is being rolled out regionally due to the limited availability of both the new transmission fluid and tool kit availability. The dealer rollout was determined by paid warranty claims from TSB 16-NA-175. It is anticipated that the new transmission fluid and tool kit will be available nationwide by late January or early February 2019. Once the new transmission fluid and tool kit is available the detailed service procedure will be loaded into GM Service Information (SI) as a Technical Service Bulletin (TSB). TSB’s 16-NA-175 and 18-NA-177 will be eliminated from SI. An additional Global Connect Message will be sent to announce these changes.
Selected dealers will receive a separate Global Connect Message this week advising how to obtain the new Mobil 1 Synthetic LV ATF HP transmission fluid, delivery of the no charge tool kit from Bosch and detailed service procedure.
The new fluid exchange procedure will require the use of the existing DT-45096 TransFlow machine and tool kit. The tool kit will ship from Bosch at no charge.
The December 2018 Emerging Issues Broadcast, course number 10218.12V will be available through the Center of Learning on Thursday, December 13. The broadcast contains a video demonstrating the procedure on a Chevrolet Colorado and details on the new Mobil 1 Synthetic LV ATF HP transmission fluid.
The detailed service procedure may seem complicated at first review. However, we are confident that once you’ve completed the procedure you will find it relatively easy.
Proper Diagnosis: Sometimes shudder is not caused by the torque converter clutch (TCC). In some instances, shudder is fish bite, chuggle, surge or vibration. Utilizing the GDS and or the PICO Scope will help confirm the issue is TCC shudder. We have seen cases of suspected TCC shudder turn out to be engine performance, tire/wheel vibration or a driveline vibration.
Please do not contact the Technical Assistance Center (TAC) seeking information on when the new Mobil 1 Synthetic LV ATF HP transmission fluid and tool kit will be available nationwide. TAC does not have any additional information.
For those dealers that are not among the initial selected group. Please continue to follow 16-NA-175 and 18-NA-177 until the new service procedure is available nationwide. We are working diligently to get the new service solution available to all dealers and will advise through an additional Global Connect message once available.
Thank you for your cooperation.
GM CUSTOMER CARE & AFTERSALES