I usually use ramps when working on non-wheel stuff. But found the ramps limiting as the shaft needs to be turned in order to get good whacks at the joint. So, stands would be the way to go.

As AyeRoll says, you have to knock the joint up the shaft until it clears the gear, then knock it out and down. I found the bar with the flat end, that comes with the wheel change tool kit, useful in levering up the joint (though a large screwdriver would also do).

Take a wire brush (and oil) to the splines before beginning with the hammer.
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1980 245 Canadian B21A with SU carb and M46 trans

Lots of beating, an inordinate amount of swearing. I've only done the lower one ($65 from FCP Groton).
Mine was worn out- totally loose. However it was quite difficult to loosen it from the shaft. The steering shaft goes WAY up inside the spline of the upper part of the lower joint. Likewise, the rack stub shaft goes well up into the lower part.
You have to get the locking bolts out first, which seemed tough enough, and then beat the bottom spline up off the rack, driving the upper one on deeper. Then when it finally clears (2 inches or so of driving it up the shaft) you reverse the process, driving the joint back down off the steering shaft.

Once everything was cleaned however, the new one slipped together like butter. Probably takes the cake for the filthiest job I've done- I guess there was a lot of PS fluid all over my rack. I was completely black halfway through the job.

Good luck, and bring your best 3-lb hammer.
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Rob Bareiss, New London CT ::: '87 244DL/M47- 234K, '82 245T/M46-182K, '89 244DL/AW70- 212K Not too distant past: 86 244DL 215K, 87 244DL 239K, 88 744GLE 233K, 88 244GL 147K, 91 244 183K