that's the truth. I replaced the clutch in the ZF out of my '01 and likened to blow out an o-ring in the process. I rented a jack and slid the trannie back about a foot to do what I needed to do, but the hard part was getting that heavy and bulky ****** back in. My advice, if you are going to do it from the ground, is to have a friend help you out. Otherwise, let a shop with a lift do it. My truck is in the shop now getting a new input shaft, synchros, and bearings put in it. By buddy is the mechanic there and he told me that on the lift, they had the whole thing out in about 45 minutes.
Luck with it.