JOHN DEERE 4300 small leak

[dfkrug]

My first 4300 rebuild thread was 15y ago, and I did not separate the part about the front axle rebuild. It starts at post #115 here:

John Deere 4300 complete rebuild

I got around to checking mine out today using an inspection mirror and a flashlight. From what I can see, the intake hose is barely touching the fuel tank; but the fuel overflow hoses are not trapped between the intake hose and the tank. I didn't see any obvious evidence of wear on the hose...

www.tractorbynet.com

I was re-reading this old thread, and it has brought back memories. It was a fun read, if I do say so myself.

In my second 4300 rebuild, I started new threads for the various repairs/rebuilds that I performed.

 

[super55]

Both wheel seals on each side are leaking. Before you go digging into the wheel seal for replacement. There's a couple small tricks you can try. First, drill a 1/16 hole in the fluid dipstick so the axle can vent and not pressurize. The other option is to replace the fluid in the axle with actual gear oil 75w-90 instead of JD Hygard.

I know JD recommends hygard for the front axle but it is not ideal. Its got too low of a viscosity. The front axle is self contained unit so if you put gear lube in the front axle you will not contaminate the hydraulic system.

I have a 4400 and 4310 that have the exact same issue as your pics showed. It's a well known problem with JDs and they still refuse to address it. There's aftermarket vented fill caps designed to address this very issue. After I went with gear lube and vented the axle the leak was so minuscule that it wasn't worth addressing. Every 8 month or so I might need to top it off.

 

[beenthere]

Just leave the dip stick fill plug loose and it will vent. Works for everything except driving the axle underwater. At least has worked well for me. And don't use the low vis Hygard oil. Straight Hygard is what I use. Again, works for me but each can plan their own way.

 

[dfkrug]

The other option is to replace the fluid in the axle with actual gear oil 75w-90 instead of JD Hygard.

I am a huge fan of using gear oil instead, even the thicker stuff, 85W-140. I use that in my Kioti, but it does take a while to put in.

Note that many tractor manuals specify hyd oil OR gear oil for the front axle.

Interesting about air expansion bladders for final drives. Many (most?) decent ATVs you buy now have them for both front and rear axles. Great idea. Why not in very expensive tractors, esp the ones with low front axle ground clearance?