Can you attach multiple Gear to the same unit?

Yes, you can attach multiple pieces of gear to the same unit.

According to RiftJudge FAQ 9165, there is no limit to the number of equipment cards that can be attached to a single unit at the same time. As long as you have the resources to pay the costs and the equipment is not already attached (because you cannot activate the Equip ability of a piece of gear that is already attached, per Rule 730), you may continue to attach additional gear to that unit.