There is a reason why OEMs keep engineers on a product even after launch. Of course there are issues that occur, especially in something as complex as a transmission. I can't think of anything that was major serious in the past with the GM boxes...they had their issues though. The flower pot on the 4L60 comes to mind. The biggest issues we had was the ever increasing duty cycles and torque upgrades coming out of Engine. It's why I did a 4L65E skunk works, a 200 mile durability 4L80, an even a HD 4L80. All these programs came from "issues". I wasn't that tuned in to FWDs. I was a RWD guy. By definition, we had more durable boxes because of the vehicle we were in demanded more. The one exception to that rule was the behemoth 4T80. This was a caddy box, over designed, over priced...but wow...smooth as glass.
I left as the 6 speeds were being developed. Hydramatic developed something called centers of expertise (COE). These islands developed design rules (which were kinda over done sometimes) that had to be adhered to when designing the new boxes. The DNA and all the lessons learned on the legacy boxes are rolled into the new boxes. It's one of the major reasons that from a design perspective, very little goes wrong. Most issues I chased as the lead development engineer of the 4L80 were manufacturing and supplier quality issues. Changing anything in the plant was near impossible with the UAW.
Other sources with "issues" were caused by dealerships "repairing" things in the box. Dealerships caused more problems sometimes then what they fixed. Lots of mis-builds. GM handled this problem by simply by-passing the dealership. If there was a trans problem, the customer simply got a Certa. Our reman site would tear down, diagnose, and rebuild the boxes instead of dealerships. Certas, by willams technology using prison labor, actually had quality numbers better than willow run. This was a good move...better cust sat. Willams tech facility is rather impressive.
"The DNA and all the lessons learned on the legacy boxes are rolled into the new boxes. It's one of the major reasons that from a design perspective, very little goes wrong."
The same thing happened on the manufacturing side. We put together a Bill of Process (BOP) to go along with the Bill of Design (BOD). We insisted that everything be the same whether we were making 6L50's in Willow Run, Toledo, Silao, or Strasbourg (Strasbourg was the only exception, they put Ravigneau gear sets in 6L45s). Any exceptions had to be approved by only a couple of people and we made sure there weren't many. The 6 speeds launched better than an other products I have ever been associated with.
I am worried that this is losing momentum on the mfg side though. During the bankruptcy period, they reorganized and the transmission plants along with the engine plants were placed under different mfg managers who also have assembly and metal fab plants. I'm afraid they are losing focus. We'll see.
If you have to jump on a mistake like that you might want to work on either psychological
problems or your own intellectual framework. I admit to occasional, grammatical errors
and it isn't in the least bit upsetting when a scholar like you down grades my paper. It
costs me zero sleep.