The Crystal Mountain is a large structure on Level 17 of Old GoBotron.
Challenge of the GoBots cartoon
Crystal Mountain was effectively the power behind Gunnyr's regime on Level 17 - inside were huge banks of equipment that blocked the weapons and ability to convert of any GoBot who visited. Only those fitted with scramblers - like Gunnyr and his right-hand GoBot Bug Bite - were able to access these functions, which obviously gave them a huge advantage in combat. This meant when Leader-1 and Turbo arrived from the surface of GoBotron in search of the missing Scooter they were at a distinct advantage, and only Dart's quick-thinking explanation that they were bumpkins prevented their capture. Scooter meanwhile had made an ally himself, and teamed up with Ace to sneak into the Crystal Mountain and destroy it, allowing his fellow Guardians to easily overwhelm Gunny and Bug Bite. The GoBots That Time Forgot