3520 Axle Seal

   / 3520 Axle Seal #1  

317140

Bronze Member
Joined
Apr 9, 2006
Messages
87
Location
North Carolina
Tractor
John Deere 3520
I noticed today that I had grease running out of the hub and dripping on the front wheel of my 3520. I am assuming that the seal is bad. Has anyone changed that seal and how big of a job was it. I have a well equipped shop that I am in the process of moving into so I guess this will be the first project. Also what kind of grease does the front differential hold.
 
   / 3520 Axle Seal #2  
317140

Likely that is Hy-Gard oil coming out the seal, and likely it is because of pressure building up in the differential gear case from increased temps.
A trick is to loosen the dip stick a bit and let that case vent, and when I did that then the leaking at the front hub stopped for the most part.

Changing out the seal in the hub is an option, but when the pressure builds then the gear lube is going to go somewhere. I let it flow out the fill hole where the dipstick is located.
 
Last edited:
   / 3520 Axle Seal
  • Thread Starter
#3  
I am not sure if it is a pressure issue. It was leaking right after I moved it yesterday. Obviously it had not built up any heat. I used it to bushhog a 5 acre pasture last week and didn't see any leaking. Got on it yesterday and there was a puddle of grease on the wheel and a steady drip behind the hub. I am fairly certain the seal must be bad. Wondering if anyone had replaced the seal and what kind of job it was. Thanks
 
   / 3520 Axle Seal #4  
Front axle uses Low Viscosity HY-Gard oil
 
   / 3520 Axle Seal #5  
Zebrafive
Thanks for catching that on the oil.

317140
There have been threads on changing out this seal on TBN in the past.
Try a search, although the search engine here doesn't seem to be the best IMO or I'm just not good at finding threads.
KennyD would be a good member to limit the search.
 
   / 3520 Axle Seal #6  
The whole pressure thing sort of makes sense, you used it for 5 acres worth of mowing and then parked it with built up pressure. The pressure remained after you stopped and pushed the low vis out and there is your puddle. I would certainly try the pressure relief before I would tear into that seal. You might get more than you bargained for.

When you stopped, the fluid stops circulating and pools where it is. That could very well be why it leaked after you stopped.
 
   / 3520 Axle Seal
  • Thread Starter
#7  
Not sure about the pressure buildup. I could see oil dripping out of the seal sitting still after driving it into my shop. I decided to pull it down while I had the time to check it out. After getting the hub off I decided to take it to my dealer because I don't have a press in my shop yet. After talking to the shop foreman I found out they average about 1 tractor a week with these same seal problems. He said they find wire, baling twine, sticks, small rocks and other assorted objects tearing in to these seals. They had it apart in 10 minutes and back together in less than 30 minutes. The only thing that hurt was the seal was around 50 dollars. Total repair ran about 130 dollars with a gallon of Hy-gard and a tube of silicone. Good thing I took it apart myself or I would have been out another 100 bucks in labor. Seems a little excessive for a simple repair. I am sure John Deere is aware of this problem and it looks like an engineer could come up with a possible fix. Oh well I guess that's what keeps the service department in business. Sorry for the rant but sometimes I feel like I can't fix things as fast as they break.
 
   / 3520 Axle Seal #8  
Not sure about the pressure buildup. I could see oil dripping out of the seal sitting still after driving it into my shop. I decided to pull it down while I had the time to check it out. After getting the hub off I decided to take it to my dealer because I don't have a press in my shop yet. After talking to the shop foreman I found out they average about 1 tractor a week with these same seal problems. He said they find wire, baling twine, sticks, small rocks and other assorted objects tearing in to these seals. They had it apart in 10 minutes and back together in less than 30 minutes. The only thing that hurt was the seal was around 50 dollars. Total repair ran about 130 dollars with a gallon of Hy-gard and a tube of silicone. Good thing I took it apart myself or I would have been out another 100 bucks in labor. Seems a little excessive for a simple repair. I am sure John Deere is aware of this problem and it looks like an engineer could come up with a possible fix. Oh well I guess that's what keeps the service department in business. Sorry for the rant but sometimes I feel like I can't fix things as fast as they break.
There have been quite a few 3x20's with seals going out. Another thing to keep in mind, if you are lifting allot of weight often, make sure you have plenty of 3 point ballast to take the stress off the front axle.
 
 
Top