420 Deere Garden Tractor Hydraulics

buckten

New User
Broke while rototilling. Engine runs fine. PTOs all work but no transmission or hydraulics. I checked linkages and couldn't see anything. Pulled out the two pressure relief valves and cleaned. No leaks, no burn smell, just nothing happens when trying to go forward or reverse or 3 Pt and other hydraulic do nothing. I am presently hunting for a pressure meter that fits so I can measure that. What should the pressure read and is there anything else I should be looking at?
 
Check the "roll" pin in the driveline to the transmission. Pin shears, shaft from engine turns, but shaft into transmission does not.

Take off seat and deck mounting the seat to access.
 
Check the "roll" pin in the driveline to the transmission. Pin shears, shaft from engine turns, but shaft into transmission does not.

Take off seat and deck mounting the seat and fuel tank to access.
 
As Roger said, check for integrity of the driveline all the way to the hydro input shaft.

If the shaft going in to the hydro IS turning, likely the "charge pump" (Key # 20) has failed.

Could be just that pin (Key #13) that drives the gerotor pump has failed.

<img src = "http://jdpc.deere.com/pimages/MP56/MP5653_________UN01JAN94.gif">
 
The drive shaft is turning going in and out of the hydraulics pump. The rear electric PTO engages fine. This happened when I got a flat tire when rototilling so it certainly makes sense that it may be a pin. Is this a hard repair? And do you have a recommendation on where to get a part? I have the seat and deck already off, but am somewhat restricted in may mechanical ability (although I did pull the engine to put in a new starter several years ago). Thanks for the quick responses everyone. First time user here.
 
Bob is right, I am wrong as no pin used in driveline. Since rear pto is working, driveline is okay.

The pin driving charge pump has probably failed.
 
Thanks. Is this an easy fix (once I get the part). Getting ready to leave on vacation so I have not taken a good look at how hard it will be to open up the pump.
 
The charge pump is held on by two bolts, where the driveline from the engine goes into the transmission. You have to remove the driveline to remove the charge pump housing. Mark the housing so you know which way is up.

You need to get the pin, if broken, from John Deere.
 
(quoted from post at 14:15:38 07/19/16) The charge pump is held on by two bolts, where the driveline from the engine goes into the transmission. You have to remove the driveline to remove the charge pump housing. Mark the housing so you know which way is up.

You need to get the pin, if broken, from John Deere.

The pin (part # M88049) is about $21 at the DEERE dealer. (YIKES!)

Sometimes the gerotor gets badly worn or cracks in half, as well.
 
[Thanks Bob. Just got back from a long vacation and will try our local Deere dealer (mainly home mowers and tractors) here in Western Washington. Wish there was a complete online Deere dealer.
 
I know this is a lot to ask, but does anyone have fairly step by step instructions on how to change the pin. I'm sure I have to unhook the two hydraulic connections at the top and the shift mechanism on the side. Got the pins yesterday. People are correct - over $20 for a very small pin. Wow! Thanks all for your help.
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top