1720d yanmar hydrolic leak

[Eagles eye]

It's purchased this tractor with a loader, diesel engine and 4wd. ($4500) at an auction. Everything works well but when I went through and changed all the fluids I noticed the trams was a little low. After changing and bringing to proper levels I ran and worked loader for an hour of so. The only leak I found was underneath at the rear of the front diff. There seems to be a sleeve covering the drive shaft for the diff and the oil is either running out of there or at the rear seal of the front diff.
Can't his cover be removed to better see where the leak is COMMING from and why would it be leaking hydrolic fluid there? Not engaging front wheel drive .
Also anyone know how well these hold up? Did I get a good deal? Seemed low for a compact and has 875 hrs on a working tach....thanks!

 

[winston1]

There is a rubber boot about midway on the drive shaft cover. The cover will slide together at that point to allow inspection or removal.

Your leak could be coming from the 4 wheel drive drop box (hydraulic/transmission fluid) or the 4 wheel drive (90 weight).

Here is a parts drawing from Hoye. Yanmar Tractor Parts: 4WD INTERNAL

Tough little tractors. May take a little time to know if you have a good deal or not.

 

[Eagles eye]

There is a rubber boot about midway on the drive shaft cover. The cover will slide together at that point to allow inspection or removal.

Your leak could be coming from the 4 wheel drive drop box (hydraulic/transmission fluid) or the 4 wheel drive (90 weight).

Here is a parts drawing from Hoye. Yanmar Tractor Parts: 4WD INTERNAL

Tough little tractors. May take a little time to know if you have a good deal or not.

Thanks allot, I will look at the site and do some inspection this evening.

 

[Eagles eye]

What is the drop box? Can't find that anywhere on the net or Hoyte ....it is transmission/hydrolic fluid. The front diff is not leaking....

 

[winston1]

What is the drop box? Can't find that anywhere on the net or Hoyte ....it is transmission/hydrolic fluid. The front diff is not leaking....

The drop box is where the drive shaft comes out the front of the transmission. See picture #1 in this thread. Not a 1720 but similiar. Yanmar Tractor Support Message Board • View topic - Lost front wheel drive on my 4x4 tonight

Here is a 1510 setup. Similiar to what you have. #28 being a similiar seal to what you have leaking. http://www.hoyetractor.com/mm5/merc...Store_Code=HTE&Category_Code=YM15104WDSHIFTER

 

[Car Doc]

I agree with Winston's evaluation if you are sure its hydraulic/trany oil (JD 303 or universal tractor fluid) rather than 90wt it most assuredly is the pto drop box at the rear of the drive shaft tube and running to the front and getting out at the front diff.

Once you slide the front tube or cover back as he described it will be a little clearer to you how the drive shaft works and you also may see the problem why the 4wd is inop the balls may be missing or the splines stripped in the slip joint?

 

[Eagles eye]

I agree with Winston's evaluation if you are sure its hydraulic/trany oil (JD 303 or universal tractor fluid) rather than 90wt it most assuredly is the pto drop box at the rear of the drive shaft tube and running to the front and getting out at the front diff.

Once you slide the front tube or cover back as he described it will be a little clearer to you how the drive shaft works and you also may see the problem why the 4wd is inop the balls may be missing or the splines stripped in the slip joint?

Thanks alot for the wisdom from both. I will get under it tonight and see what gives. The 4wd does work I just have not been using it.

 

[clemsonfor]

Not engaging front wheel drive .

I think he said it may not be working.... because you said this, see above.

As far as how these hold up, pretty good. they will run for thousands of hours. The engine is the same that you will find in JD compacts for the last 30 years and still today. In the 80's Yanmar made JD's compact line and were just rebranded as Jd's.

Most here love our tractors and think there as good or better than any american compact ever was.

 

[Car Doc]

Yeah thats what threw me he must have been saying its leaking even w/o engaging 4wd is how I read it now I know it does work. But it is working so hes ok glad of that. Oh and welcome! We are here to help so ask away.

 

[Eagles eye]

Yeah thats what threw me he must have been saying its leaking even w/o engaging 4wd is how I read it now I know it does work. But it is working so hes ok glad of that. Oh and welcome! We are here to help so ask away.

Thanks, yes the 4wd does work. The leak is at the drop box and I have ordered the seals. Seems like a good tractor. I moved several tons of gravel with it yesterday and it worked well....sure I will be on here often as I work through getting to know this tractor. Been looking for a compact for several months and found nothing under 6500 dollars. Bought this one for 4500 so I think this was a good purchase.
Thanks for all the help!