Bryan/Apostle/Dan- I'm not sure what regular Hy-Tran cost, but last fall I bought a 2gallon jug of HyTran Ultra (all they had), and my wallet got something like $45 lighter. I would've preferred to loose that weight on the other side of the pants, but that's life...
On the subject of hydraulic fluids- there are some things that you just DON'T want to have in your hydraulic system, due to the things that occur in there. One of the biggest reasons why you don't want foaming in a hydro system... is because foamed hydraulic fluid can contain sufficient amounts of air, with just the right amount of fluid... to become a diesel engine. One of my fluid-power demonstrations for hydraulic light-rail brakes utilizes a electrohydraulic unit pumping into a test-load (cylinder with pressure transducer and load-cell). I empty the EH unit, and pour in just a little kerosene, then run the load with minimum cylinder stroke. After it froths, the cylinder pressure jumps from 10 bar to well over 200 bar, and a pressure relief blows... because the Kerosene ignited. It's not unusual for shop guys to mistake the smell of the hydraulic fluid used in these LRT's with Kero, and we need to make very certain that they don't make that mistake.
I don't demonstrate, but make the same explanation for airbrake systems, as it's not unusual for pipefitters to use solvents in assembling brake lines... when you slam 150psi into a brake caliper, or well over 200psi into a compressor housing, anything flammable in there tends to go off.
But there's more to fluids than that... all sorts of lubricity stuff, thermal transfer properties, viscocity changes, but also compatibility with seals, metals, and any other lubricants into which it might come in contact.
Ken- Phooiye on you! I didnt' cut the !@#$'n frame... I cut TWO @#$%'n frames!!! Both were pseudo-nasty, but donated good ends, and the job's so darned clean, that unless YOU lookie real close, you won't be able to tell WHERE I did it. Best of all, on my non-existant budget, I'm putting the thing together (and doing all the stretching, etc) using parts that'd otherwise end up in the scrap pile. I think I deserve a purple heart for saving otherwise doomed Cub-lives, but all you're vending is purple-nurples and cyber-bruises... back into to your crucible, 'ya heavy-metal-smokin' hippie!
...And if I don't like that diesel, I've got a 327 GM Marine motor waiting... but I really wanted to keep that one set aside for a brute-strength 184 with an SM465 and Rockwell axle... mebbie 4wd...