# Another hydro issue



## agmx73 (Apr 27, 2013)

New member here. I have read through most of the posts that I can find about this issue so I will try to keep this short. I have a 2005 or 2006 FS550 (Sears 917.276700) with over 400 hours on it and a Hydro-Gear 400506 (Sears 318-0510) that won't go up the slightest incline when it gets warm/hot (after about 10 minutes) It will still go both forward and backwards on level ground. I have removed the transaxle and I'm trying to find the correct hydro oil (20W-50). I have been to my local Tractor Supply Company as well as 5 automotive places with no luck. Could someone please give me the brand and proper name of the correct oil to use? I would also like to verify that it should hold about 79 ounces of oil. Last question; what is the best way to flush it? I would like to flush it before I put new oil in it but I'm not sure what to use. Thanks in advance for your help.


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## agmx73 (Apr 27, 2013)

I found the actual Hydro-Gear Service Manual on line and was able to answer my own questions. However, after changing the fluid, the same problem remains. It works great until it gets hot and then won't make it up the hill in my back yard going forward (I didn't put the mower deck back on just in case I wasn't done with this). Reverse does not seem to have the same problem. Any ideas on what to do next to make this tractor work in the forward direction?


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## wjjones (May 28, 2010)

Welcome to the Forum!..agmx73.. Its your belt mine did the same thing twice they just get stretched, and burnt out. You can also purge these hydro gear transaxles to but after you install a new belt.


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## Argee (Sep 17, 2003)

agmx73 said:


> I found the actual Hydro-Gear Service Manual on line and was able to answer my own questions. However, after changing the fluid, the same problem remains. It works great until it gets hot and then won't make it up the hill in my back yard going forward (I didn't put the mower deck back on just in case I wasn't done with this). Reverse does not seem to have the same problem. Any ideas on what to do next to make this tractor work in the forward direction?


Have you purged all the air out of the system. The one thing any hydro manufacturers recommend is purging after changing fluid as air is compressable and will interfere with hydro operation and giving the same symptoms you describe..


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## agmx73 (Apr 27, 2013)

Thanks for the responses. I tried a new belt first. That seemed to fix it, however, 10 minutes later I couldn't get up the hill in my yard in forward so I had to reverse up it. Then I dropped the transaxle and changed the oil. I have purged it twice, and had to add oil each time. I will try a third time this afternoon. Hopefully this will fix it.


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## agmx73 (Apr 27, 2013)

I actually ended up purging the system 8 times. The last 4 times when I would follow the procedure in the manual, it appeared that all of the air was out of the system. Then I would drive it and it would get progressively worse over about the next 20 minutes, When I would check the oil, the level had dropped about 1/2 an ounce each time. I just spent the last 30 minutes going up and down the hill in my backyard without issue. As soon as I sharpen my blades and put the mower deck back on, I will try it for real.


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## Argee (Sep 17, 2003)

That's good news. Hope it continues to improve!


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## wjjones (May 28, 2010)

Argee said:


> That's good news. Hope it continues to improve!




Yep let us know if it does ok, or not. I try to purge the tranny every 30 to 50 hrs of use.


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