I'm not sure. There is no 4wd propshaft in the way under the oil pan, so i think you can take them out from above. maybe you'll have to dissolve the carbon build up on the top end of the liner, with DOT4 brake fluid. That will eat allmost anything and free stuck piston rings.
Dotn forget to change oil once you've contaminated your engine with it. a glass full of brake fluid neutralises the lubrication of a sump full of engine oil.
when i rebuilt the heads on my 5245 i had it running with brake oil soaked piston rings, to break down any possible carbon obstruction of the piston rings. I changed the oil after an hour of idling and driving around with no load, when the ground valves were seated.