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.
Edit:
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.