"Jamb" nut? are you talking about the nut that holds the piston on the end of the rod?
The service manual actually shows a bolt here, but refers to it as a "retaining stud"
torques to 225 ft lbs, with lock-tite medium strength.
I may have used a stout 3/4 inch impact wrench to get mine off.
or maybe the threaded "head"( also called a "gland") with the seals in it ?
Also torques to 225 ftlb, I think it said something about hydraulic sealant.
I think the tilt cylinders came apart without undue effort, one of the boom cylinders I used a 36" pipe wrench, a 6 foot cheater pipe & a torch to heat it up some.
My machine is LX865, but manual shows the same for the 885.