Also, as Jerry mentioned, be sure to leave the plug out the first time you let it down after filling. Otherwise, if you're LUCKY, the bed will not come down all the way. If you're UNlucky, you'll blow the seals out of your hoist!
On mine, I just went to the farm store, and bought 2 gallons of their generic hydraulic fluid.
And, as has been stated before (but can't be repeated often enough); make darn sure it's adequately braced if you have to go under it! If at all possible, work from underneath the truck.
