Based on my own experience - '86 RRC ZF4HP22 auto - it's a PITA & I do have a level concrete surface & the tools incl jack & adapter plate plus an engine crane to make it easier.
Had mine off twice, once to do the rear engine crankshaft seal & the second time to sort out various leaks by replacing gaskets & input seal. I did take Clutch A apart to check the friction plates but all was fine. If you do this then THOROUGHLY clean all items to remove the very fine sludge before reassembly as this is what gums up the governor.
I got the parts from these. Click on your gearbox for a blown up pic. Very helpful, take phone orders with card payment & fast delivery.
https://jpat.co.uk/zf.html#