i have used 2x4s across the hole in the floor and ratchet straps around the ends to get the trans off the floor and onto a jack. Unless I jack the truck way up, I can't roll the jack and trans under the truck. If I do that it's too high for the jack to raise. With two guys and a floor jack it's doable, only just. Not fun. Once you get the trans raised with the straps, put the shift lever back on so the inside man can use it for a lever to hold the trans straight up and down while perched on the jack. In the heavy truck world there are trans jacks that have arms useful for holding big, tall gearboxes but I don't know where you might rent one.
Before you start trans installation, IT IS IMPERATIVE that you use a GOOD alignment tool or an old clutch-gear shaft to line up the clutch with the pilot bearing BEFORE you tighten the clutch bolts. There are also plastic reproductions for this purpose. Use one or the other to grease the clutch splines and the pilot nose but not so much that grease flings off the shaft when you start it up. Also if you use too much on the nose of the pilot, you risk forcing the bushing out of the crank when you cinch the bolts down. That's one method for getting pilot bushings out.
If you have taken the clutch out or have a new one, grease the splines and work the disc back and forth on the input shaft (clutch-gear) to spread the grease before you install the clutch. If there is an existing clutch in place use the alignment tool to spread the grease.
Hook up the clutch linkage and do an approximate adjustment of the throw-out bearing,
a) so the bearing stays in place and
b) so you can release the clutch if you need the trans to move one way or another for that final push into the pilot bearing.
Insert the guide pins you made. Grease them too. Remember not to make them too long or you cant get the left upper one out. Likewise the bottom ones that have to clear the clutch. for the bottom you may just want to use longer bolts but remember if they're too long you can't get them out.
One you get the trans raised the and straps off, roll the whole shebang forward to engage the clutch and guide pins. Now you're on your own It's just brute force mixed with finesse till the trans is home and you can remove the guide pins and install the bolts. Do not let the trans hang from the clutch at any point or you will bend the disc and have to start all over with a new one.
