It is alarming I read of so many transmission issues in vehicles for the past few years and in particular since 2016 or so. And it is across most brands of vehicles. Even the 6 speeds have reported issues, but GM has the issues with 8 speeds and 9 speed it seems.
GM even has now taken to trying different fluids in each of it's transmissions. A mystery and question as to why all of a sudden, these transmissions are so touchy with even the type of fluid they can tolerate.
I've tried to keep up a bit with what is going on in these newer transmissions and I think there may be one common denominator with the issues they have besides quirky transmission controllers (TCM).
The common denominator for issues I think may be the new modulated slip torque converters. Unlike the older "lock up" TC, these new assemblies have clutch surfaces that allow limited slip under some operating conditions. Purportedly, this is to "dampen out" engine power pulsations due to use of AFM and also keeping engine RPM down for fuel efficiency. The combination of the engine ECM and TCM trying to optimize efficiency and produce torque at lower engine RPM has reached critical mass I am thinking.
I am not sure about all this, but I have seen pictures of the innards of the new torque converters and how the thin clutch and metal surfaces are worn and even turned blue from heat caused by "normal" slippage. Well, at least, that is one possible issue, but there are others it seems in this balancing act of engine and transmission interplay.
The only thing worse to me is the use of CVT in newer vehicles. So far, they seem to be relegated to use in smaller lighter vehicles, except for some now larger CUVs.
It's frustrating to think that newer vehicles are not shaping up to be as durable or as reliable when we see these type of issues arise. I question whether we can rely on keeping a vehicle even 5 or 6 years without constant concern for some type of major repair to power train components. So much going on with electronic control systems in vehicles today and the mechanical counterparts that they manipulate.
Is the hardware up to par? Is the software they are using "correct" for proper operation? Are the materials and design of the mechanical elements meeting specified parameters for durable and reliable operation?
Well, it's trash day for me today. Got to get the bins out to the curb. Hoping for all it's not our vehicles that have to be carted out there some day. . .