ʻO ka pahu hydraulic transmission gearbox, i ʻike ʻia ʻo hydraulic transmission, he mea ia e hoʻohana ai i ka mana hydraulic e hoʻouna i ka torque a me ka neʻe ʻana ma waena o ʻelua shaft.Hoʻohana nui ʻia nā pahu pahu hydraulic i nā kaʻa koʻikoʻi, nā mīkini hana a me nā noi kai no ko lākou kiʻekiʻe kiʻekiʻe, maʻalahi o ka kaohi a me ka hilinaʻi.ʻO ka pahu pahu hydraulic hoʻoili maʻamau ka mea i hoʻokumu ʻia me nā pā hydraulic, nā mīkini hydraulic, nā hoʻonohonoho hoʻonohonoho, nā valve hydraulic a me nā mea ʻē aʻe.