Longtrac 320 3 point bouncing

[long320]

Anyone have experience with hydros on a 2000 Longtrac 320? It bounces at the top and is almost impossible to get it to stay anywhere but all the way down or up. The implement falls to the ground as soon as the tractor is shut off. I have had a hard time finding any info on this tractor. Similar to a Long 2310 I read. When I got the tractor it had water in the hydro fluid. I flushed twice and refilled. I checked the filter tonight and it was awful, full of trash and a little milky fluid. Ordered a new filter, any chance that fixes my problem? I would love to find a manual for it if anyone knows where I can get one. Thanks in advance.