The THM700 was renamed "4L60" (RPO MD8) following the new General Motors naming convention, when the electronic version, 4L60-E (RPO M30), was phased in.
The 4L60-E family of transmissions use 2 shift solenoids, initially called Shift Solenoid A & Shift Solenoid B, later changed to comply with OBD II (On Board Diagnostics revision 2) regulations to 1-2 Shift Solenoid & 2-3 Shift solenoid.