John Deere 4300 complete rebuild

[mjncad]

Overall that hub looks in great shape, especially considering how the rest of the tractor looked when you got.

It's so nice to see USA and Link-Belt boldly etched on the bearings. I'm tired of seeing barely legible China and India on everything anymore.

JD's hydraulic fluid is the same color regardless of viscosity. I used the low-vis when I did my first 200-hour service, and switched to regular viscosity at 400-hours.

At no time did the fluid ever come out of the tranny or front axle looking red like ATF.

[kennyd]

Two weeks ago I changed the hyd/tranny fluid in my JD 790 with 400hrs on it. It all came out looking red just like ATF fluid!! I am the third owner of this tractor so I can't say what the two previous owners did (if anything) with regards to changing the hyd/tranny fluid. Honestly, I have my doubts that either one of them changed the fluid but I can't say for sure. What I thought was interesting was that JD recommends their low viscosity Hygard fluid that I put back in, but it looks more like weak Karo syrup, not red like what came out of mine?? So maybe it was changed sometime in the past.

I'm in SC where it doesn't get real cold so I used three gal's of the low viscosity Hygard, and one gallon of the regular viscosity Hygard. I don't guess it will hurt anything to mix it???

JD's hydraulic fluid is the same color regardless of viscosity. I used the low-vis when I did my first 200-hour service, and switched to regular viscosity at 400-hours.

At no time did the fluid ever come out of the tranny or front axle looking red like ATF.

The fluid that Yamnar uses at the factory IS red, just like ATF. Dealer told me it's to find leaks easier? Who know's...but it is red for sure.

[dfkrug]

The fluid that Yamnar uses at the factory IS red, just like ATF. Dealer told me it's to find leaks easier? Who know's...but it is red for sure.

Yeah, I have been told that the color in THF is there to help find leaks.
I have never bought HyGaard or any other oil from JD. I know that the
rental yard that has owned these machines for the past decade has
switched from their Chevron THF to something else....I do not recall what.
I will find out. I am still a little disturbed by seeing rust on some parts
that were submerged in oil all this time.

[Kyle_in_Tex]

It seems amazing that there is no inherent wear on the big bevel gear. Rust must have come from condensation while it sat waiting for a hard working person like yourself to take it home and fix it.

Keep up the posting, I love seeing the "innerds" of mechanical stuff....

[dfkrug]

It's so nice to see USA and Link-Belt boldly etched on the bearings. I'm tired of seeing barely legible China and India on everything anymore.

I have so far found bearings from Timken, made in USA, Canada, and France.
I have found Hoya bearings from Japan. And, in the gearbox, I just found
my first bearing made in Russia!

Also, Hema makes the hyd pumps, Funk Manufacturing (a subsidiary of
JD) uses an Eaton HST in the transmission, Modine makes the oil cooler,
and I found no name on the front axle. Spicer seems to own up to the
axles on the JD3120, which looks similar.

[dfkrug]

It seems amazing that there is no inherent wear on the big bevel gear.

Yeah, the gears are in great shape....they are of cast steel, rather than
the machined forged gears I find in the gearbox. One bad bearing, however.

I was hoping I would get more responses from others on comparitive
manufacturing of similar sized tractors. I was at a JD dealer yesterday
and I took a magnet to a JD3120 (replacement for the 4200/4210), and
one of the 4x20s. The photo below is from the 3120. The good news is
the 4x20 does not use any aluminum that I can detect. The not-so-good
news it the 3120 uses MORE aluminum than the unit it replaces. (See
photo.) The axle housings, the center section, AND the PTO cover are
all Al. JD HAS improved the weakest part, however. The 3PH lower
lift arm pivots are considerably beefed up. Due to many failures here, no
doubt.

Is the 3x20 the only tractor in the 3000# 30-35hp class that uses Al
for structural castings? There is no substitute for first-hand reportage,
and I am here to learn.

[dfkrug]

OK, next I removed the kingpin/hub housings from the main axle housing.

You can see the axle in the first photo. It is quite hefty, tapering from
just over an inch in diameter to about 1.5 inches. I had some surface
corrosion, even though it is supposed to be covered with oil all the time
(see the yellow dipstick in there?). The 4 bolts that hold this together
are glued on with a pink thread locker, so you need a serious breaker
bar to get them off.

Next you see the inside of the kingpin housing. You are looking at a large
circlip, about an inch inside the casting. Even if you are a big dude with
giant hands, this was tough to compress. My pliers are pretty good, but
once compressed, how to you pull it out? Thankfully there are two access
notches that allow you to get some screwdrivers in there. (These notches
are only there so the bevel gear can fit inside.) This is not for circlip
virgins!

Once out, the bearing was not up to my standards, so I replaced it. Just
$5 from a bearing supplier.

[JohnDeere4300]

Thanks for all the pictures!.... I've been following all your posts, and the gears looked good.

Where is the 'sight glass' in the other picture ?

[dfkrug]

Where is the 'sight glass' in the other picture ?

There is no sight glass on the axle. You can see the yellow dipstick if
you look inside the axle housing in the first photo above.

[Johndeere3720]

Wow! This is one incredible project! I am disipointed in the 3x20 series deeres for all that aluminum. I will be excited to see the finished project!