I'm gonna guess that's a bug then.I'm using steel and sapphire/ruby/peridotite picks currently. They can pick up any other kind of gearbox, too, but not bedrock ones.
Now that you mentioned it, interestingly enough a Tinker's Construct steel pickaxe IS indeed able to break bedrock gearboxes, but ordinary ones don't work.
HSLA pickaxes seem to work, too. Alright then, was just confused because it all worked before the update, and all other gearbox types are still harvestable with ordinary old picks.