1996 Yukon, 4L60E, lost 3&4, so I drove it around town with 1&2 for a while. 115k miles.
2007 Colorado, 4L60E, lost reverse, so I drove it for a bit just had to push it out of parking spots, had a junkyard trans installed and sold the truck, 70K miles.
1997 Suburban, 4L60E, would throw a P1870 code after it got warmed up, and then would shift hard. Just reset it with an OBD scanner and it would be fine for a while. Sold it like that. 215K miles.
The short version? 4L60Es SUCK!!!