JD 4300 hydro drive 4

[wrede]

Oil leak from rear side of front axle pivot. Possibly leaking seal? How is pivot lubed? Axle oil? Possibly pinion seal bad. How difficult is axle assembly removal? How about seals?

 

[JordanFTW]

What exactly do you mean by "front axle pivot", where the center of the axle mounts to tractor?

Here is a copy of the service manual, it will be of great assistance to you
Tm1677 4200 4300 4400.pdf

 

[Boondoggle]

Jordan,
I also have a leak in the front left side and downloaded the service manual. Thank you for providing that. Do you know where in that manual I can find a diagram of the assembly and seal so I can better understand what I am getting myself into before I pull my front end apart on my 4300?

 

[Boondoggle]

/Where can I find an exploded view of this assembly for my 4300 front seal?

 

[kennyd]

/Where can I find an exploded view of this assembly for my 4300 front seal?

www.jdparts.com

There is a quick tutorial linked in my sig if you need help with it. The same basic system the parts counter uses at the dealer...

 

[wrede]

The outer front axle seals are shown in the repair manual. There are two types in 2001, as they must have changed the design about then. It goes by serial number. One has a large stopnut holding the spindle assembly together. The other, like mine, had a snap ring. I assumed based on the description, that it would easily come apart. No! You'll need a hydraulic press, and it will take quite some force. I used a 20 ton press, and it was straining. I gave it a rap with a hammer, and it came apart. The new seals are different. The old one was a face seal, with the seal made between the seal and the shaft. The new one, though not explained, fits tight to both surfaces, and the seal is made between the two halves of the seal. A little ticklish to set it, but I have no more leaks. I was able to do it in less than 3 hours, first time around, including changing the oil and drilling out and removing a stripped plug on the bottom of the outer housing. It's metric. Within 2 months the other side leaked, and I had that done in less than 2 hours. I made a special breather plug to replace the dip stick, as I couldn't find a breather anywhere.

 

[Boondoggle]

Can you help me identify this? What is this called

Front left
This is where I believe my leak is occurring.

 

[wrede]

That is the spindle housing and is shown on page 8-16 of the TM1677 technical manual. It explains that the final drive housing (the outer axle shaft assembly) has to be removed (the part I was mentioning earlier). I have not had the spindle apart, but it looks fairly easy, though you'll need access to a press. The entire front axle, left, middle, and right is one large oil reservoir. Have you checked oil level? Does it leak sitting, or only when running. I found that when running, the pressure built up in housing, as evidenced by a hissing noise when I checked the oil after running (engine off). I wondered if the pressure forced the oil past the seal.

 

[Boondoggle]

I checked The front reservoir last night and it was low, or possibly empty. There was pressure when I removed the dipstick. I noticed the leak this weekend when the tractor was in my garage, but didn't notice if it had a leak when running or shutoff. Before I disassemble I was thinking of filling it back up to double check where it is leaking. I have to get some hydraulic oil to fill it back up first. I will hopefully try that tonight.
Thanks

 

[wrede]

It holds 7.4 quarts total. There are pipe plugs at the bottom of each final drive (5mm key, I think) as well as one under the center diiferential. You may want to check to see if you have any moisture in there, as when I drained it, the oil was milky.

 

[dfkrug]

The outer front axle seals are shown in the repair manual. There are two types in
2001, as they must have changed the design about then. It goes by serial number.

The model # of the front axle is hidden under paint next to the fill hole. All versions of the front axle
(4 total, I think) are shown in the manual. Tho 2001 is the last year of this tractor series, the actual
tractor may have the earlier type.

 

[Boondoggle]

I filled up the front reservoir tonight , it took about 1/2 gallon, maybe less, and not running nothing is leaking, started it up and no leak, turned the front tires back and forth, no leaks. drove it around a little, no leaks.
Hmmm. I will use it more this weekend and report either way.

Besides Power Steering, and front wheel fwd, what does the front hydraulic reservoir run?

 

[wrede]

Before I made a "breather" plug for the front axle, I would leave the dipstick a little loose so that the pressure couldn't build up. The front axle assembly is its own reservoir for bearing and gear lubrication, separate from the main drive axle and hydraulic system. The power steering hydraulic loop is connected to the rear high pressure system. There should be no pressure in the front axle unit. Even the dealer seemed surprised that there is no factory supplied breather on my axle.

 

[kennyd]

Here is an older thread on the breather issue: http://www.tractorbynet.com/forums/john-deere-owning-operating/181090-front-axle-pumpkin-vent.html


And another from the same poster: http://www.tractorbynet.com/forums/...ing/179279-more-leaking-axle-seals-vents.html

 

[wrede]

Adding a breather to the pumpkin is a rather large project. I had the front axle out of mine because I thought the pinion seal was leaking. When I got it apart, the seal was dry. I then found the real leak, which was one of the fuel injection nozzle return hoses, one of the little short pieces. The fuel was leaking down the front of the engine, and on to the axle assembly exactly where the pinion seal would be. Yes, those pivots were dry and a bit rusty. I cleaned them up and greased them on reassembly, and left the pinion seal alone. I'll have to recheck the oil level in the front axle, but I also think you could run the axle a bit low if the dip plug was left loose, and there was any seepage.

 

[Boondoggle]

I noticed a small puddle of liquid near the left front wheel this morning on my way to work. I like the breather idea. There has to be an easier way to release pressure. A loose filler cap scares me where it could come off and the opening be exposed. I will have to verify that it is hydraulic fluid when I get home and then try it again with a loose cap to see if pressure is the reason for the leak, not the seal, or would it be both? If it is leaking, would the problem of the pressure buildup blow the seal so that would also need replacing?

 

[wrede]

The pressure wouldn't have built up overnight if the tractor was sitting. The buildup of pressure is about 10 % from 65F to 125 F, which I'm simply guessing could be the oil temperature when your driving it. 10% is about 1.5 psi, not a lot. It would certainly get by a worn seal, but I'm wondering if maybe something got wrapped around the spindle housing and damaged the seal. Now that it is leaking, I believe the only answer is to replace the seal. As I said before, I haven't done it, but it doesn't look too bad. Looking at the manual, it looks like the first step is to remove the final drive housing, which is the housing around the final axle shaft. It has a few bolts and a slot to pry it off, and doesn't have a gasket, as I recall. Then you would remove the spindle housing from the main axle housing. Disassembly requires removing some snap rings and pressing the gears and bearings off. If you keep track of the shims, it should go back together (press) without worrying about measurements. The manual actually shows two seals on the drawing, and maybe the outer one is like a dust cover to prevent stuff from getting into the real oil seal. If you find seepage behind the axle/wheel flange, you should replace the outer seals while you have it apart. I read the thread about the breather hose, and agree that the oil wouldn't go out unless it was overfilled, or at a large angle, allowing oil to get into the hose. The suggestion to use two breather hoses is a good one, but you'd have to drill a hole in the left side axle housing. Not a big deal, but not sure how you can avoid getting chips in the housing. Use grease, or a vacuum, and also a magnet afterwards, but drain the oil first.

 

[samhudson3]

The dipstick on my 1999 4300 HST has a breather slot. My tranny cap does as well.

 

[Boondoggle]

Sam, are they factory, or aftermarket or home made? Do you have a picture of them?

 

[Chef Pa]

The dipstick on my 1999 4300 HST has a breather slot. My tranny cap does as well.

Have a 99 4300 also, dipstick on this one doesn't have a breather slot. Good info in the thread links from Kennyd - thanks.