tmux/vim scroll problem

I apologize if this is a known issue, but I am trying to do the whole "copy/paste" thing with vim and tmux panes and having a problem.

Basically, when I enter copy-mode while in tmux and vim, I cannot scroll down or select more than what is on the current screen. If I'm not in vim, and just in the regular terminal then the copy-mode will let me scroll up or down.

This is really annoying when it comes to copy-paste large files in vim between panes. The only two workarounds I've used were to just 'cat' the file to standard out and then copy that way, or literally copying one page at a time in vim.

Is this a known issue? Is there a workaround. I hope this makes sense. The only other example I've found that seems to describe my issue is located here: http://stackoverflow.com/questions/21585305/scroll-vim-window-in-tmux-copy-mode . The suggestion there seems to just be a vim plugin. This isn't completely viable since I am often ssh'd to other machines that I can't always install plugins on.

Any suggestions?

EDIT: Thanks everyone for the responses. I will explore some of the "built in" (registers) options since I want to avoid having to manage plugins on remote machines.