Ford 3600 rear lift all or nothing

[DarbyCrash]

1979 ford 3600, recently purchased and have noticed the rear lift is either all the way up or all the way down when the lever is engaged. Has both levers for draft control and lift control. With implement on the ground, lift does not engage until the lever is almost to the 2,3 position and when it does, it travels straight up to top position. Same going down, lift doesn’t engage until around 2,3 position and slams right on the ground. Cannot float or pick lift position. Still in the process of “renewing” tractor and replacing broken or worn out parts and am getting to the hydraulics. Any insight is appreciated or what to check for next on the issue. Also the lift speed lever is stuck on fast. Tried to rotate it and completely broke off btw.

 

[kwbretired]

What position is the draft control lever in, all the way up or all the way down. It should be all the way down.

 

[zzvyb6]

Cracked O-ring in the pressure relief valve. Same cause for symptoms on other brands. When you unscrew it from the trans, careful not to let broken pieces fall in.

 

[DarbyCrash]

What position is the draft control lever in, all the way up or all the way down. It should be all the way down.

It is all the way down. But still same symptoms regardless of draft control position.

 

[DarbyCrash]

Cracked O-ring in the pressure relief valve. Same cause for symptoms on other brands. When you unscrew it from the trans, careful not to let broken pieces fall in.

10/4 and it can be changed without removing top cover? This is my first tractor I've owned, sorry for the newbie questions.