I recently rebuilt a Land Rover R380 5-speed gearbox that I'm going to fit to my Discovery I, and while I had it apart, I discovered something strange about the oil pump. At the rear end of the layshaft, there's a machined recess in the aluminum extension housing that holds the layshaft rear support bearing and the oil pump back-to-back. Normally, when rebuilding one of these boxes, you're intended to first remove the oil pump body; this gives access to the back of the layshaft support bearing, which can then easily be driven out with a press. On my gearbox, the oil pump rotors ran directly in a machined-out recess in the aluminum housing – there is no removable pump body.
All of this means that the outer race of the support bearing could be pressed in, but not removed, as there is no access to the back of it. We ended up fabricating a tool to address this: the old support bearing inner race was cut into thirds, and two of these sections were inserted so that the lip on the inner race pieces was behind the bearing's rollers. At this point, a socket with a shoulder (or similarly shaped piece of stock) can be inserted from the rear, through the oil pump drive hole. We then put it on the press, and began to drive the socket toward the front of the extension housing. If it's sized appropriately, the socket will tend to spread the inner race sections against the rollers (so that the lip remains firmly seated on the rearward side of the roller), and simultaneously carry the bearing outer race out with it.