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View Full Version : Oil for ZTR Hydraulics


jtboney
06-03-2005, 12:44 PM
The owners manual specifies you use 15-50 synthetic oil in my Gravely PM34Z mower in the hydraulic drive system. I discovered that my dealer filled mine with 15-40 NON SYNTHETIC oil (and the cheapest stuff they make at that) so I decided to change mine (at 8.3 hours)

I bought a filter from the dealer ($18) and some Mobil 1 15-50 oil from Advance Auto. The filter they sold me has 10 milacrons on the side. The one that came on the mower had 40 milacrons on the side of it.

I'm sure both of these filters were made by some off shore company that Gravely found by price shopping.

My questions:

Which filter is the CORRECT one for this application?

There is no way to get all of the oil out of the system. You can only drain about 1 1/2 quarts at the time. I did this twice and refilled it. This should have diluted the old oil down to about a 1-4 ratio. (3 parts synthetic and 1 part regular) Is this ok?

I am sending these questions to Gravely also but they haven't been the most responsive to emails in the past. They did help me solve a pto engagement problem I had a while back, but they tend to give very vague answers.

Any help you can give me would be much appreciated.

JT Boney