'56 420W pto problem

[valve guy]

new to me 420. i bought it and pto shaft rotated slowly
while disengaged. engage pto and it spun up to what
appeared to be 540 rpms. bring it home, attach bushhog
and the pto lever wont engage and makes a grinding sound.
disengage output shaft to the bushhog and the pto on the
tractor will engage spin ip to 540.

1) could my problem be the pto clutch?

2) from a non-mechanic who changes oil and greases zirks,
how difficult is this repair?



thank you

 

[Hayfarmer]

The 420 is not live PTO, you will have to have the clutch down to engage PTO. Not unusual for them to turn a bit when disengaged but stop with pressure on the shaft. Using the brush hog you need to have an overrunning adapter in the pto shaft or it will be dangerous and tear stuff up

 

[valve guy]

ok, not live, thats fine. with a load on pto it wont spin, unloaded it will spin.

thoughts?

 

[old]

Broken coupler which is what engages the PTO

 

[valve guy]

question about broken coupler answer. when i hear broken that sounds to me like wont work. given my pto seems to work without a load, that sounds like clutch or worn.

can you please explain further?

 

[old]

The couple slides forward and back to engage and disengage the PTO if it is broken the PTO can/will spin with out a load but put a load on the PTO like say a brush hog the PTO will not spin and have power. Had that happen to y JD B years ago and the coupler had t be replaced

 

[jd2cylman]

(quoted from post at 11:25:26 07/02/22) question about broken coupler answer. when i hear broken that sounds to me like wont work. given my pto seems to work without a load, that sounds like clutch or worn.

can you please explain further?

The two pieces rubbing together drive the PTO output shaft by friction. Once you put a load on the PTO output shaft, the load is stronger than the friction drive of the broken surfaces.
It could be the coupler. Or it could be the drive gears in the transmission. With a transmission PTO, it doesn't take much drag to make the output shaft spin without a load on the shaft. Shut off the tractor and engage the PTO. If you can turn the PTO output shaft by hand, you have serious problems. If you can turn the PTO output shaft and the engine turns (with extra leverage), you aren't engaging the coupler fully when running. There is another coupler at the rear of the transmission where the PTO output housing bolts to the transmission case. Check there first. Three bolts, and the PTO output assembly comes off. Shouldn't be any oil loss when removing the housing (as old as it is, maybe a tad).

This post was edited by jd2cylman on 07/02/2022 at 11:12 am.

 

[Jim.ME]

First thing here is to determine which clutch you have, transmission driven or continuous running as JD called them. 420s did not have an independent PTO option, but a continuous running PTO (aka two stage clutch) was available on the 420s. The clutch pedal has to be used to engage either the transmission driven or continuous running PTO. The transmission driven one requires the clutch pedal to be pushed completely down to engage the PTO which also stops the tractor travel. The Two-Stage clutch (common term for the continuous running clutch) requires pushing the clutch pedal completely down to engage the PTO (yes, the travel will stop as well when this is done). However, once the PTO is engaged, pushing the clutch pedal about halfway down should stop travel but allow the PTO to stay running. The two-stage clutch is kind of like a clutch in a clutch. One disc drives the transmission the other drives the PTO.

Go to: https://techpubs.deere.com/ and you can download a free copy of the Operator's Manual. Click on Equipment Publications. Enter 420 in the search box for model. Click on 42o in the drop down that appears, and you should see several choices including the Lawn and garden 420s, available for several world markets and in several languages. It appears there are some serial number breaks so having your serial number will help you chose the right one along with reading the description. You can download your tractor's manual and it will explain how both work, to help you identify yours. Then it may be easier to find the problem.

 

[buickanddeere]

Had one that needed some metal ground off the PTO engagement lever . To allow it to rotate farther into the engaged position .