mylittleCJ5 is correct of course, but I have to admit that I couldn't help myself and it can be fairly educational to fiddle with the gears to see how your transmission really works. The T-15 is a sliding sleeve design, rather than moving great clusters of gears it moves a sleeve arrangement back and forth with reverse and first controlled by one sleeve then third and fourth by another. Also the way your shift lever works can be enlightening. But, I admit that I rebuilt my transmission so how it works came along with getting the job done. You will notice that the shift forks have a plastic substance on them, it's actually nylon. The stuff is extremely tough to stand up to all that goes on in a transmission. But as was said above, if you fiddle with the trans, make sure both front and rear sleeves are in neutral along with the stick. Then simply make sure the forks slid into their groves and you are good to go. I'd put it on and synch down a couple bolts then run it through the gears to make sure everything is where it's supposed to be, then finish installing the bolts.