On the Volvo, since the shifting is in the upper gear housing you can remove the lower unit without removing the whole outdrive. However, keep in mind that when you reassemble it, you have to line up both the water tube and the vertical driveshaft. In my experience in doing it on the OMC Cobra (very similar other than the shifting is in the lower unit, so you remove the whole thing before splitting the upper from the lower) it is easier to get both lined up if the lower unit is in a drive stand and you lower the upper gear housing down onto it. Also, sometimes it will get stuck on one of the O-rings that seal off the water passage from the oil chamber (esp units used in salt) and so the lower can be tough to get off, esp if not removed for a long time. I rigged up something to make it easier.