I helped a friend sas his taco. We tried using the trans cooler in the rad as a power steering cooler, but it wouldn't work. The trans cooler needed more pressure than the pump would put out. His powersteering fluid boiled out of the resivor till we switched back to the stock cooler.
Other than this mishap the 90 or so steering box on his 2.7 liter equiped taco works flawlessly!
