For me your description is not complete enough. Is this a new condition with some background leading up to it?
A L4200 can have a Glide Shift or manual transmission. You should provide this info.
A L4200 may or may not have a FEL. If you have one, assuming it is a Kubota one, provide the model number i.e. LA681
I do not think the L4200 has a mid pto but some tractors around that size do and they have a mid pto.
It would be helpful if you clarified the presence or absence of a mid pto
Are you saying the pto wont turn but then you talk about a change when moving a backhoe lever.
Is this condition happening when an implement is connected to the pto shaft?
Is this just an observation of the shaft with nothing connected but when the BH is mounted?
Hydraulic issues are complicated and many members avoid the questions which are not very clear.
I cannot find a free WSM which makes it harder to study the L4200 systems
This is a helpful group but you need to be patient. Weekend posts get less attention in my experience as it is only old ones like me who are on line on a nice weekend
Dave