155d Hydraulic Chatter

[NH_Yanmar]

I have a Yanmar 155D which I have had for a year and I love it. Today it developed a chatter (Small jerking movments) when I raised the loader or tilted it, even though I had nothing in it. My landscape rake was doing the same thing when I raised it. I thought I might be low on fluid, but I checked it and it is fine. I'm hoping it is the filter, but the manual I have shows the filter in a spot that doesn't exist. There is an access cover on the other side in the same spot the diagram shows where the lever to raise the drawbar is.
Any help will be appreciated as to what else could cause the symptoms or as to the location of the filter.

 

[professor]

The 155d that I owned had a hydralic filter. Your problem sounds like a clogged filter,water in the oil or a stuck relief valve. The hydralic filter is located at the bottom of the tranmission case. There are three bolts in the filter cover. There will be a pipe in the center. Remove bolts,carefully pry off filter cover. The filter is a reusable wire screen type. If the filter is not damaged, clean in solvent and let dry, Replace filter and add new fluid(John Deere 303 or equivalent.

 

[roger_scotty]

Its been a while since I did this, so someone please correct me if I left anything out. Start by look about 5 inches below your Hi/Lo shift lever on the right hand side of the transmission housing. There is a roundish cover with a steel hydraulic line coming out of the center of it. The cover is mounted with three bolts. Loosen that hydraulic line where it goes into a short section of hose - its the low pressure suction line. Now take off the three bolts and pry off the cover. Sometimes the cover will be stuck. uhhh...you did drain the transhydraulic oil first I hope? The drain is the plastic plug on the other side. Under the 3 bolt cover is a gasket and a rubber grommet holding in a cleanable wire mesh filter. My bet is that you need to clean that filter. The system is not under pressure at that point, so the gaskets are reusable if not too badly torn up and if you can keep them from leaking. I use a light smear of silicon sealer

If that doesn't do it then it is probably the relief valve chattering. Let us know and we can probably find a volunteer to do a write up on how to fix it.
Good luck...half the fun is the maintenance...

 

[NH_Yanmar]

Thanks for the help. I thought that was a more likely place for the filter. It was really dirty. I am still waiting for the liquid gasket to dry so I haven't seen if the problem is fixed yet.
It's funny because I went to my local John Deere dealer to pick up the Hydro/Trans fluid and he had never even heard of a Yanmar tractor. He said "You mean the engine is Yanmar" I said "no, the whole thing is Yanmar". He went and talked to one of the mechanics ( I also wanted to know how to clean the filter). The mechanic had also never even heard of a Yanmar tractor, or even cleaning a filter. He said they replace them. I guess Yanmar is one of the best kept secrets there is.