The 4L60E was first seen in 1993 model cars and trucks. The predecessor to the 700R4 was now an electronically shifted transmission. Not only does it have shift solenoids, and torque converter clutch control, but it also has electronic pressure control. It has gone through many changes and updates since it first began 25 years ago.
This unit has a number of issues that are common failure points. The 3-4 clutch is definitely at the top of the list. The engineers at GM new this clutch was going to be a problem from day one. They were right. This clutch pack has gone through many updates in order to withstand the loads that it has to hold up under. Another weak point is the band. The band is used in 2nd and 4th gear. The reaction shell was a high failure item early on, but went through a number of engineering changes and the final version of this part became a reliable part. These three are definitely the top failure areas, but there are many other smaller factors that would cause the unit to fail. The valve body has a few high wear items that need attention during rebuilds. Some of these are commonly the root cause of clutch failure.