It is of moderate difficulty but certainly doeable. I would suggest taking the money you would pay a mechanic and buy some tools. Noteably a transmission jack, those OD trannys can be heavy, some good jackstands, and an alignment shaft to help line up the tranny. I would also suggest replacing the pilot bearing since it is an inexpensive part which can negate a clutch and, if you have any oil leaks, the rear main oil seal. Its a matter of having it all apart anyway. Needless to say the throw out bearing, clutch plate, and pressure plate should be replaced.