I swapped out my diff and am not sure how to get the rear axles back in. Obviously i just need to push them hard enough, but i can't get enough leverage on anything.

 

Any tips to get them back in?

What car are you working on? If it is a ea81 or ea82 you can disconnect the lower shock/strut mount to let you get some more movement out of it. Also disconnecting the trailing arm may help with that as well.

it's a 97 Legacy

 

When taking them out i just popped them out with the wheel lug by leveraging against the diff... but don't have anything to leverage against going the other way now.