sorry for the short response, I thought someone else would chime in here..... anyway, I've removed the gearbox and tc on my D1 in one piece. I used a crane/lift
thru the driver's door (like the manual says) to raise the new tranny. To remove it I just unbolted everything and laid the tranny on my belly and slowly slided it onto a "moving" dolly.
What are you up to? I can imagine it's even easier on the 90 since you have more room to work with. I don't know if the gear box is heavier on the manual box than the auto box.
BTW, I use no power tools or air compressor and I did all the work by myself (although Adrian did help me with part of the removal).