Cant get transaxle into engine

You've probably seen it a million times, but I am having a very hard time getting the transaxle spline to go into my b18 engine. I have both outside the car and I've been at it for about 2 hours now. I've done this many times with rwd configurations, and I just usually put it in gear and have someone else rotate the output shaft back and forth until it goes in. The kicker here is, this is a open differential transaxle, so putting it in gear won't stop it from rotating, and someone else spinning one of the axles only rotates it when there is nothing holding the input shaft, and me pushing the transaxle into the engine holds it still. 

Nothing to do with clutch alignment as I made sure it was aligned and I took the transaxle off only 3 days ago

also should be mentioned that I'm doing this with manpower, no jacks so, What do I do?

Long bolts (like really long) threaded into the engine block with the heads cut off to create dowels for the transaxle to slide on.

Cut slots in the ends to make them easier to remove later.

Generally its all about the alignment in the other axis that makes this difficult.

Get the shaft as perpendicular to the clutch face as possible and gently rotate the crankshaft until it all drops in place.

If you've done this quite a bit, then the splines on the clutch disc and/or the transaxle could have burrs on them making it more difficult.  So inspect carefully and clean up the faces of the splines.

Nothing to do with clutch alignment as I made sure it was aligned and I took the transaxle off only 3 days ago

So you never removed the pressure plate in those 3 days?

In reply to Vigo :

yes, just replaced the throwout bearing

There is a diff pin going through the middle of the differential. If you can stick something like a large flathead screwdriver far enough into the diff to get stuck on one side of the diff pin and not spin, it will allow you to turn the whole diff carrier and rotate the input shaft like you're wanting.