L2501 hydraulic leak

[LostinArk2]

Good morning all.
I have owned a couple of BX models since 2001 and there have been maybe half dozen times I have had to top up the hydraulic fluid. Each time it was only a few ounces. Neither tractor had a front loader or bucket, just mower.
A few years ago, my sister and niece got a L2501 with a front loader and tiller for their property. It seems like they have to top up the fluid on a regular basis. Because of a lot of factors, it hasn't been used at all for the last couple of months. I went over to help them to grease the fittings and check all the fluids this past week. It was more than a gallon low on hydraulic. Now, just sitting there unused, there has to be some indication of where it went. Crawled underneath and looked at the whole frame. No sign of fluid leak at all, including around the filters. Opened the hood and no oily dirty spots. End to end on all the lines from the loader - fittings all tight and clean.
Sorry for the long post, but I am buffaloed. That much fluid has to going somewhere, but where??? Any ideas where to look next?
Thanks.

To add - I have ordered some tracer dye to see if that helps to track down the leak.

 

[number two]

Is the tractor parked on a level spot when the sight glass is checked -and the loader lowered to the ground?
Perhaps there is no leak,but isn't correctly checked.
Really can't imagine where else it's going.
Good Luck!

 

[2manyrocks]

When my L2501 was delivered, it seemed like the HST fluid was very low in the sight glass and the front axle was no where full, either. One possibility is that the fluids haven't been checked until you checked them carefully.

 

[RjCorazza]

Given your thorough check of the tractor, I suspect @number two is correct that the fluid level has just not been correctly checked in the past. The sight glass on my last Kubota was very sensitive to checking the fluid level. I let it sit on a level surface overnight before checking the sight glass level, and it was consistent.
You didn't mention any hydraulic attachments, but a new unfilled attachment will also use up some fluid on first use.

 

[LostinArk2]

Tractor is always parked on level surface. Front loader was on when delivered and never taken off. I like the suggestion that front axle was not full. Any way, red dye should be here for the weekend and I'll get it in, top up the fluid and run it it for an hour or two. Then let it sit and see where that leads. Thanks for the suggestions.

 

[Ricn]

my 2501 has not had any leaks and it sits on concrete shop floor when not in use. I find checking the site glass hard to see the fluid level. If you are seeing no fluid leaks anywhere I can't imagine you would have one but you say they have topped it off several times? Odd to me. Hope the dye finds something.

 

[LostinArk2]

Just as a quick update. added fluid and ran it for about 15 minutes - up and down the road, front loader up,down curl. Back home parked it on a tarp. came back 15 minutes later to find fluid on the tarp but still no definite leak point. Called dealer to pick it up and see what they could find.. They finally got it on Friday. Now the wait begins. Will update later