hydraulic oil for tilman dump trailer

[outdoorsman0490]

I have one of the last new tilman dump trailers before they went oob. It has worked fine since I have had it, but today it did not dump all the way up, both on a heavy load, but then also on a light load. I noticed it seems to be low on hydro oil in the reservoir at the lowered position (for some reason). I think there might be a pin hole or something somewhere, but I have yet to see any oil where I park it. I know it needs more hydro oil in it, but I don't have an owners manual for the trailer. Does anyone know or have a reccomendation as to what the exact kind of hydro oil I need to get. Thanks

 

[Walt41]

I run dex/merc transmission oil in both of my JDJ dump trailers and change it yearly. I know some guys run hydro oil and others run trans/hydro oil like that used in shuttle shift compact tractors. I would find the pump manufacturer and see what they recommend.