PTO clutch repair

[FotonOwner]

I bought a Foton FT254 at auction.
The handbooks are dreadful and cover hardly anything on the PTO mechanism. The clutch does not seem to disengage the PTO to allow the PTO gear to be engaged. When the connecting rod from the clutch pedal to the PTO clutch leaver is disconnected, the clutch lever arm can be rotated by hand through 360 degrees and offers little resistance.
It seems to me that something is missing or broken but there is no exploded view so I can only guess as to what is supposed to be attached to the inside of the clutch shaft. It looks like it would be easy to remove the top plate from the gearbox (which also holds the PTO clutch shaft) and look inside but not sure if that would mess anything up.
Any ideas as to how this shaft attaches to and operates the clutch? Is it safe to remove this top plate?

 

[Soundguy]

you might get some hits in the chinese section...

soundguy

 

[FotonOwner]

you might get some hits in the chinese section...

soundguy

Thank you for the response Soundguy, I will check it out.
Here is a photo of the gearbox top showing the bolts and clutch linkage if that helps.

I also have a problem with the engine oil pressure dropping when it heats up (half and hour or so). The pressure drops from 0.4 MPa to around 0.2 or less at idle and the red light comes on. I have changed the oil and filter and no change. Any ideas what I can do to locate the fault?

 

[PILOON]

Looking at your photo, I'd say the shift lever is easily removed via 4 bolts.
Do that in neutral as easier to re-assemble.
Below that is the transmission cover with the PTO lever to the rear, looks like maybe 6 bolts holding that cover on.
I assume the rear lever is the PTO shift arm.
It probably moves a fork back and forth to engage/disengage the PTO.
At best there could be simply a sheared roll pin to guide the fork in/out or worst a bent fork.
Pin=easy fix, fork=replace or weld to fix.
Just looking at the positioning, I'll bet some guy wearing size 12 boots tripped on that lever more than a few times and sheared the pin.
I don't believe you have much to lose by lifting the covers and having a look.

 

[Soundguy]

for the oil pressure, I think I'd slap a mechanical gauge onthere and see what it is really doing. if fine.. then change the sender.

if not fine.. then uh.. well.. dropping oil pressure is usually the result of high clearances.. so might be time to service the oil pump and check the main and rod bearings.. cm inserts / bearings if it has them.. etc.

soundguy