Can't Read Hydraulic Fluid Level in Sight Window

[tharperidaho]

Model: L3410 HST

Doing 200 hr. maintenance and no longer have visiblilty of hydraulic fluid level in sight window. I noticed before starting the maintenance that I could not see the fluid level (tractor has been sitting a while), so figured I'd fix that after changing filters. There was a bit of leakage on the transmission case, but not much on the floor, so I don't think it was very low.
I never saw the level appear as I filled and ended up running fluid out the fill hole. Which of course is embarrassing...
I calculated what I put in, let that amount out and started figuring out ways to see how much fluid I might have. I ran the tractor onto an incline, sight window downhill, and still no fluid level. I raised and lowered the front end loader and again, saw nothing. I tried going up and down a small embankement to see if that would change anything. No luck.
Can the window cloud and cause this problem, or is there perhaps an air bubble keeping the fluid level out of the area? I don't know if this is a simple window into the casing or if there is some sort of column there that could get an air bubble in it. Any ideas would be appreciated.
Oh, is there some sort of dye I could put in the fluid to make it more visible? When I drained the fluid back out, it looked dark, but perhaps not dark enough.
Any ideas would be greatly appreciated.
Sincerely,
Tom Harper

 

[rjcorazza]

I replaced the window in my L3410, which made seeing the fluid level much easier. It was some years ago, but I recall it being a simple job.
Order a new one, and pop it in. Sight windows for hydraulic fluid are always a pain... My current L4060 has a standard dipstick.

 

[D2Cat]

The window is like $8. Pop the old one out and push the new one in. Then it's clear again.

You may have it so full you can't get it to lean enough to see through the sight glass. May have to put the sight glass on the uphill side to see the fluid.

 

[tharperidaho]

Thanks you guys. I ordered a new window. Should be good to go in a few days.

 

[200mph]

John Deere makes a dye to improve visibility. I am guessing others make it as well. Here’s a link as an example: https://www.greenfarmparts.com/John-Deere-Oil-MT3668-p/mt3668.htm

 

[tharperidaho]

I bought a new window, but by the time it arrived, the weather got very cold and I work in an unheated out building. I was worried about the silicon drying adequately if I replaced the glass, so I opted for another fix. I decided to try polishing up the current window, much like you'd clean up a headlight on a car. The surface was quite rough, so after a thorough cleaning, I sanded lightly with 320, then worked my way through grades of wet/dry paper - 400, 600, 1200, 2000, 4000 using water for lubricant. The glass cleaned up quite well and I have very good visibility of the oil level. If it were warmer, I'd probably go ahead and replace the window, but the polishing works well enough. Just thought I'd report an alternate fix that works pretty well.
Thanks again to everyone that offered advice.

 

[captmikem]

John Deere makes a dye to improve visibility. I am guessing others make it as well. Here’s a link as an example: https://www.greenfarmparts.com/John-Deere-Oil-MT3668-p/mt3668.htm

This is GOOD stuff, got it on Amazon. Also when you have a hyd leak (had one on my backhoe) You notice it! Even a small one, you notice it because of the pink foam.

M

 

[lugbolt]

Just take the window out of the transmission. If it's overfull, you'll know real quick. Let it run out until it slows way down, reinstall the window and then watch it. May have to add a little at that point. I don't remember if that window is screwed in (hex) or pressed in. If pressed, you may want to pick up a replacement before removing the old one. If oil was running out of the fill port, you're WAYYYY overfilled...like several gallons or more. On an L3400, coming out of the fill port is roughly 6 gal over, speaking from experience....but it's a completely different transmission than a 3410 is.