I have read several posts about alternative hydraulic oils that can be used in the Self Leveling System (SLS). One of them is Aeroshell Fluid 41. I also read that the oil should NOT be petroleum based, but only mineral based or else it will eat all the seals in the system. I went to an airplane supply shop and they had the Aeroshell 41 but it says on the can that it is petroleum based! So.... does anybody have first-hand knowledge whether or not I really can only used mineral-based oil and whether or not I can use the Aeroshell 41 ???? Thanks!