Adding 5th gear to a 4 speed transaxle?

[Blaster2005]

I did use the search option and found nothing. I was wondering if I can remove 5th gear from one transaxle and install it into to a 4 speed transaxle? I think someone told me I could remove the shim pack from the 4 speed and then add 5th gear, I can't remember if this correct. If anyone has done this before or knows how to please post a reply. Any advice would be appreciated!

Thanks, Mike