John Deere 4020 PTO

[Pennerosa]

Hello have a 1969 4020 Power shift I am planning to work on this winter. Suspect I need to rebuild the PTO but looking for some advice first. I have noticed 3 things: 1) PTO will slip under load - can run a 9ft haybine, but will slip if try to run a baler; 2) PTO brake not working, have to shut engine off to hook/unhook implements; 3) When PTO engaged there is a very noticeable drop on the transmission oil pressure gauge - barely holds on the the "min pressure" line, but as soon as disengage PTO the pressure gauge jumps well past the line. Any input appreciated thanks.

 

[wore out]

Hello have a 1969 4020 Power shift I am planning to work on this winter. Suspect I need to rebuild the PTO but looking for some advice first. I have noticed 3 things: 1) PTO will slip under load - can run a 9ft haybine, but will slip if try to run a baler; 2) PTO brake not working, have to shut engine off to hook/unhook implements; 3) When PTO engaged there is a very noticeable drop on the transmission oil pressure gauge - barely holds on the the "min pressure" line, but as soon as disengage PTO the pressure gauge jumps well past the line. Any input appreciated thanks.

Set up the linkage between the PTO lever and PTO valve as directed in the Service Manual, then check PTO clutch and brake pressures at the test ports in the clutch valve body.

If adjusting the valve linkage doesn't help, likely you have a leak in the PTO clutch or the seal rings that feed it that will require a split at the flywheel housing to access.

As to the PTO brake, accessing that requires a second "split" between the clutch housing and transmission.

In addition to seal or brake lining failure there's a pin in the brake mechanism that can fail requiring a "field modification" or possible a replacement of the damaged casting. I don't remember the exact details of that, if you ask lower down on the page in the DEERE-specific Forum there's a guru or two that can get more specific.

One more thing, I NEVER remove or attach an implement PTO shaft to a tractor with engine running "just in case" and suggest you adopt that policy with this and any other tractors you work with.

PTO's can maim or kill, and QUICKLY.