John Deere 4300 complete rebuild

[dfkrug]

Hey guys , the final drive/ axle housings on 4000 and 4000 tens are all alumium.

The center section (the final drive/range shift/PTO gear case) on the
4200/4300/4400 is definitely cast iron/steel. Not only is my unit's gear case
iron/steel, my parts book lists only one part number for the 4x00 for all
transmission types. That indicates the "transmission case" (YZ80608) is the
same for the whole series and all manufacture dates. Since the
4210/4310/4410 is an incremental upgrade to the other series, I would have
expected the use of the same rear castings. Did that later series switch to
aluminum for the center section? And the changes from the 4x10s to the
3x20s were much greater. Can anyone report on their own 3x20?

 

[dfkrug]

More on taking apart and analyzing my engine:

My first photo is the insides of the front gear case. If you look closely, you
can see white hash marks highlighting the index marks on the gears. These
must be lined up for proper valve and FI timing. The crank has to be rotated
many times before these marks line up since some of the gears have an odd
number of teeth. Correctly assembled, you don't have to adjust the FI timing.

Next are the pistons. This engine is a 1.5-liter direct-injection engine, so
the pistons will look a little different than some other port-injected Diesels.
There are four steel inserts (arrows) in the 4300 pistons, but none in the
earlier 955 piston. The latter engine had a shorter stroke, for a displacement of only about 1.4-liter. The skirts have some funky cutouts in them, too. A
lot of thought must have gone into these piston designs!

With everything apart (photo 4), it only looks like a mess. Believe-it-or-not,
all the parts are carefully set out to be assembled exactly where they came
from.

 

[Brimstone10x]

I have only replaced the housings . But if it was mine I would look into repairing them. John jd tech

 

[dfkrug]

...the mounting bolts bosses crack with a B/H.

John, I know that JD uses an unusual subframe for their hoe mounts to the
4300. I have seen the part unmounted, but not mounted to any tractor.
Does the subframe use the same mounting bolts that the axle housings
use to attach to the final drive gearcase? These bosses on the axle
housings are the ones you have seen broken? How often have you seen
that and only when a hoe is used? I will fabricate something stronger when
it is time to do my subframe.

 

[Brimstone10x]

Hey , There is no subframe , just two steel plates that bolt to the final drive housing mounting bolts. When the mounting bolts are torqered correctythere isnt normaly problems.yesthis is only with a B/H installed. John

 

[dfkrug]

Hey , There is no subframe , just two steel plates that bolt to the final drive housing mounting bolts. When the mounting bolts are torqered correctythere isnt normaly problems.yesthis is only with a B/H installed.

Yes, I have seen the 2 brackets, and I had a photo, but I can not find it.
They look to weigh maybe 50 lb each and do not go under the tractor. I
would still refer to them as a subframe, but not a very substantial one as
they do not reduce the bending stresses on the middle of the tractor. This
is another questionable design trade-off. I hope someone with a 4x00 or
4x10 with hoe can show a photo of how the brackets mount. When I make
my subframe, it will not be done that way.

 

[dfkrug]

It's a John Deere Christmas! At least until the Discover card bill comes due.

This is my first batch of parts, though I have already bought lots of hoses
from other sources already. I elected to have the parts truck-shipped, so
I don't have to be as concerned about damage to my hood and other panels.
Worked out fine, and the cost was reasonable. It took over an hour just
to match all the part numbers up to my packing list.

As for the tires, they are blems, but easily worth the $63 cost each. 2
thumbs up for Nebraska Tire.

 

[kebo]

Man, I bet that's gonna be a whopper bill for all those parts!! I just bought a few filters and some hyd/trans oil and other stuff for a 400 hr service and it was over $150. I hope they gave you a discount for all that stuff?


Time to get started on putting some parts of that 4300 back together. I'd say you're moving along pretty good with this project. Look forward to more pic's!

 

[Kyle_in_Tex]

Great thread, thanks for detailing and posting. I'm interested to read if you determine what killed the engine for sure. I've not seen or heard of one coming apart yet like you are doing. My rear brakes have clutches on them too.

My 4310 has aluminum rear axle housings. I've seen cast iron housings break on this websight painted all different colors too. The secret for these is not to sideload any implement too hard. Meaning, if you have a box blade, don't try to back up or push on dirt that hasn't been upset yet. It is meant to pull forward putting the system in tension. Pull forward all you want until all 4 wheels have spun not a problem. But, back up, or worse yet, back up and turn hard giving a side load with a ground engagement implement and you are asking for trouble.

Are you having the block bored or doing it yourself with heavy honing stones? You got about .0098" of an inch to come out.

 

[dfkrug]

Great thread, thanks for detailing and posting. I'm interested to read if you determine what killed the engine for sure. I've not seen or heard of one coming apart yet like you are doing. My rear brakes have clutches on them too.

My 4310 has aluminum rear axle housings.
.
.
.
Are you having the block bored or doing it yourself with heavy honing stones? You got about .0098" of an inch to come out.

There is no doubt the engine was destroyed by the broken air hose
(see post #21).

I was just looking at the specs and parts listing for the 4310 and I see that
it is exactly the same weight, and the axle housing part diagram looks
identical, but has a different part #. I figured that the housing must be
Al, since the weight would be 30 or 40 lb more for the steel, at least.

The block has been professionally bored .25mm (.010) oversize, plus
honed. It did not clean up pefectly, but I think it will work.