JD 4300: opening up the gearbox to repair broken PTO and range shift

[dfkrug]

I am starting this as a new thread, but it is really just one chapter in my
concurrent thread,
2001 John Deere 4300 HST tractor extensive repairs and refurbishment:
http://www.tractorbynet.com/forums/parts-repairs/247806-2001-john-deere-4300-hst.html

This is my 2001 JD 4300, and I need to repair the PTO, which turns,
but makes noise, and does not brake when turned off. Also, the range
shift shaft is broken off flush with the gearbox housing, leaving the
transmission in LOW range.

I had both of these problems with my 2000 4300 tractor, so I am not
expecting any big surprises here.

Pix are before and after cleaning in prep for lifting off the 3-pt cylinder
housing.

 

[dfkrug]

First I drained all the hydraulic oil and removed the inlet filter screen.
That leaves about a cup of oil in the bottom of the sump, so I
removed the PTO cover to clean that out and see what's in there.

It does not look good. I recognize the 4 brake engagement levers
on the right side of the first photo, apparently attracted to the
magnetic drain plug. Also broken pieces of the brake friction discs
are evident.

I lifted off the 3-pt housing and see why: the brake basket has
broken in half! All the engagement levers and their pins fell out
(second photo). One of the brake friction discs seems to have broken
up, but the others and the plates remain in place. The PTO clutch
looks OK.

 

[Ductape]

Wow !

I always enjoy your threads going deep into the bowels of your tractors. I consider myself very mechanically inclined, but would never attempt half the repairs you do on tractors. I learn quite a bit from your threads on repairs.

 

[dfkrug]

After cleaning up all the innards, here is my collection of parts.
The hyd fluid suction filter was quite covered with small metal
fragments, mostly from the clutch and brake.

All the gearbox gears and bearings seem OK.

My plan is to eliminate the PTO brake instead of fixing it. The
downside to that is the PTO shaft will spin even when the lever
that mechanically engages it is OFF. That's due to the inherent
nature of these motorcycle-type wet clutches. There is a lot
of drag when disengaged, especially when the fluid is cold. This
tractor's PTO engagement lever is very smooth and easy to
operate, much more so than the last 4300 I had.

The third photo shows the PTO brake with broken parts removed
and the large rear aluminum bulkhead about to be reinstalled.
If you look closely, you can see that there is only one PTO brake
friction disc remaining.

So is everyone with a 4x00 or 4x10 tractor doomed to eventually
breaking their PTO clutch or brake? My guess is not if
you don't turn on or off the PTO at high RPM when running a rotary
mower or worse, a chipper. Be gentle, and don't lend out your
tractor.

JPINCA also bought one of the 4300s from the same local rental company,
and his also had a broken PTO brake basket. And range shift shaft.
http://www.tractorbynet.com/forums/john-deere-owning-operating/163261-4300-range-shift-repair.html

 

[jpinca]

After being inside one of these, I'm now very careful to gently shift between the ranges and minimize the stress on the PTO brake.

I idle the engine and then disengage the PTO slowly rather than move directly from engage to disengaged. I suspect the breakages are due to operator ignorance or indifference- mostly engaging/disengaging the PTO at full speed. I think these rental tractors only ever had a tiller attached, so the brake breakage seems kinda strange. My mower or chipper seem to put WAY more stress on the brake, even when done gently.

 

[kebo]

My plan is to eliminate the PTO brake instead of fixing it. The
downside to that is the PTO shaft will spin even when the lever
that mechanically engages it is OFF. That's due to the inherent
nature of these motorcycle-type wet clutches. There is a lot
of drag when disengaged, especially when the fluid is cold. This
tractor's PTO engagement lever is very smooth and easy to
operate, much more so than the last 4300 I had.


http://www.tractorbynet.com/forums/john-deere-owning-operating/163261-4300-range-shift-repair.html

Just curious, but can you tell us why you decided to not replace the broken/damaged parts? Is this just a cost savings move??

 

[rekees4300]

So is everyone with a 4x00 or 4x10 tractor doomed to eventually
breaking their PTO clutch or brake? My guess is not if
you don't turn on or off the PTO at high RPM when running a rotary
mower or worse, a chipper. Be gentle, and don't lend out your
tractor.

For rotary mower I always raise it then idle engine before engaging or disengaging the PTO. So far no problems for 12 years. The PTO level is sometimes hard to move but think that's just a characteristic of a 4300? I have only loaned my tractor to a neighbor once. When he bought it back he apologized for not filling it with gas! :shocked: When I told him that wouldn't have been a good idea since it's a diesel engine his face became a tad red!

 

[dfkrug]

Just curious, but can you tell us why you decided to not replace the
broken/damaged parts? Is this just a cost savings move??

No doubt the parts are expensive, but that is not the primary reason I
am going without a PTO brake. I don't think you need one and it makes
the PTO lever harder to operate.

I did not have to do much to fix the last 4300's brake, tho one friction disc
had cracked. I replaced one friction disc on that unit's PTO clutch. You have
to buy clutch packs as a set and 2 y ago that was $400. I was fortunate to
find a single disc in a pile of spares.

 

[dfkrug]

I think these rental tractors only ever had a tiller attached, so the
brake breakage seems kinda strange. My mower or chipper seem to put WAY more stress
on the brake, even when done gently.

Most of the 4300s were rented with tillers, but when they were first purchased the
rental yard still offered 3-pt mowers and box blades. Those were sold off years
ago.

Breaking the PTO brake running a tiller just shows that turning the PTO on and
off at full RPM was often done by renters. The previous group of tractors also
suffered many PTO breakdowns (JD 955).

 

[RoyJackson]

So is everyone with a 4x00 or 4x10 tractor doomed to eventually
breaking their PTO clutch or brake? My guess is not if
you don't turn on or off the PTO at high RPM when running a rotary
mower or worse, a chipper. Be gentle, and don't lend out your
tractor.

I go a bit further...when I idle down, I let it continue to idle for a short time (15-20 seconds) to let the implement spin down completely. This works for my finishing mower (Frontier, but made by Woods) and chipper/shredder (also Woods). Rotary cutters (mine is a Land Pride) can take quite a while to spin down completely.