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Discussion Starter · #1 ·
I just changed the transaxle oil on my yt359c. I drained 2 gallons plus 1 quart. I put back in 2 gallons and 1 quart. The oil level on the dip stick shows 1.25" over high. I assume there is an air pocket. I let the tractor sit over night, with the cap just sitting on the threaded opening, no change in the oil level. I put the tractor in neutral and rocked it 10 ft in each direction. I called Yanmar Georgia and their tech had run into this and he suggested jacking the front of the tractor up in the air and pushing down the left tire so the air would go up the axle and out. I did this and rotated the tires at the same time to work the gear mesh. I also held down the right tire and rotated the gears, I left the tractor jacked up with the right tire down over night, no change in oil level. I also drove the tractor around for a half mile, set over night no change. I drained the oil down to he fill mark = 1 gallon. I am quite reluctant to ignore this. Astounding such a simple procedure causing such a problem. Any ideas?
 

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Kevin, Welcome to the forums and to the Yanmar family.

You have a very nice machine indeed. I did look up the specs too.

As for the drain, flush and refill, my perspective is no different than any other vehicle. During the refill process, about 3/4 of the way full, it's best to run the machine to allow the fluid to circulate into every space needed. Then to shut down the machine, wait a few moments and check the fluid level. Lastly, top off till the full mark is reached.

Now, here's a thought. Did you also remove the transaxle filter (hydraulic filter)? The air bubble or displaced fluid could be in this region. On the YM-Series, to drain the fluid, the filter must be pulled. Some of the filters are easy to hand wash and reuse as they use an olifin media. Using soap and water will gunk up the filter, thus an air pocket could result. Typically, a little diesel and a soft tooth brush works just fine.

Your machine specs YT359 (i-HMT) mention this:
Transmission case 7.7 gal. (29 L)
Front axle 2.4 gal. (9 L)
Last page:
https://www.yanmar.com/us/wp-content/uploads/2016/03/Yanamar_2017_brochure_YT347-359_LR.pdf

Now sir, the Front Axle is about the same fluid level in your original post. Would this be the fluid your had changed instead of the hydraulic fluid?
 

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Discussion Starter · #4 ·
Kevin, Welcome to the forums and to the Yanmar family.

You have a very nice machine indeed. I did look up the specs too.

As for the drain, flush and refill, my perspective is no different than any other vehicle. During the refill process, about 3/4 of the way full, it's best to run the machine to allow the fluid to circulate into every space needed. Then to shut down the machine, wait a few moments and check the fluid level. Lastly, top off till the full mark is reached.

Now, here's a thought. Did you also remove the transaxle filter (hydraulic filter)? The air bubble or displaced fluid could be in this region. On the YM-Series, to drain the fluid, the filter must be pulled. Some of the filters are easy to hand wash and reuse as they use an olifin media. Using soap and water will gunk up the filter, thus an air pocket could result. Typically, a little diesel and a soft tooth brush works just fine.

Your machine specs YT359 (i-HMT) mention this:
Transmission case 7.7 gal. (29 L)
Front axle 2.4 gal. (9 L)
Last page:
https://www.yanmar.com/us/wp-content/uploads/2016/03/Yanamar_2017_brochure_YT347-359_LR.pdf

Now sir, the Front Axle is about the same fluid level in your original post. Would this be the fluid your had changed instead of the hydraulic fluid?
Thanks for the replies
I am speaking of the front transaxle. it is a 80-90 wt gearlub. the capacity of the trans axel is 2.4 gallons. Totally drained I got 2.25 gallons. I put back in 2.25 gallons. There is no filter on the front transaxle I am aware of, there are 2 filters on the hydraulic side. The hydraulic oil is a UTF.
The gear oil level should actually read low as I put in 2.25 gallons and the capacity is 2.4
 

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Thanks for the replies
I am speaking of the front transaxle. it is a 80-90 wt gearlub. the capacity of the trans axel is 2.4 gallons. Totally drained I got 2.25 gallons. I put back in 2.25 gallons. There is no filter on the front transaxle I am aware of, there are 2 filters on the hydraulic side. The hydraulic oil is a UTF.
The gear oil level should actually read low as I put in 2.25 gallons and the capacity is 2.4
This indeed is a wild result. Was the 80W90 normal oil or synthetic?
 

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The oil is Valvoline normal
Well, that's a good choice too. hmmm. For synthetic, I opt for 75W90 with the friction additive. Either should work.

Do you have access to the parts manual for the front axle assembly? From there, the exploded diagram should show what parts are on the inside. IF anything became loose or you can see how an air bubble can get in there, it would help determine the next steps.
 
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