Review on ACDelco GM Original Equipment 10-9243 Dexron VI Full Synthetic Auto Transmission Fluid - 1 qt: Top-Quality Performance for Your Vehicle by Kevin Silver

I replaced all 6 liters in my Mazda Miata with Mobil 1 ATF synthetic oil and the transmission in Miata, although always shifted smoothly, shifted like new again. I then changed the filter, solenoids and all 12 liters of oil in my GMC Sierras 4L60e to Mobil 1 synthetic oil. The 4L60e has always shifted smoothly, but with the new Mobil 1 synthetic the shifting is even smoother. However, with the mobil 1, there was a vibration and trembling sensation that I had never felt before. I drove the GM about 100 km with Mobil 1 atf. The vibration continued. Then I ordered 12 liters of this stuff. I pumped all I could through the dipstick hole in the gearbox, I managed to pump out about 5 liters from there, and then I poured 5 liters of Dexron back. I got the remaining 7 liters from the return line from the transmission cooler. Cooler, with the engine running, the gearbox quickly bled the remaining 7 liters of mobil 1. I replaced everything with this Dexron and it still has about 100km of driving left but the shaking is completely gone and it shifts like new again. Long story short just stick with Dexron in the GM gearbox, I now have 12 liters of synthetic Mobil 1 ATF which my GM gearbox didn't want and now I don't need it.