Today I took apart my t-5 to swap the gears, because of a cracked case. The gear in question is the gear that is on the output shaft, you can see it when the tailshaft is off. The gear that was on my trans had a couple of chips. But the one in the donor trans, was different, it was smaller width wise, and on one side of the gear it was angled. I guess mine was chipped because it wasn't angled like the other. I just want to know which gear to use. thanks to the one person that responds

With the tailshaft off the only gear you can see is 5th, unless you mean the speedo gear, which is the small gear on the shaft with the spring clip retainer.

5th gear wise it doesn't matter, but you have to use a set of gears that match, drive & driven. In other words, if the gears are different diameters (verify this by taking a tooth count) you can't just swap one gear you have to swap the gear on the output shaft and the gear on the countershaft.

If it's the speedo gear you need to use the gear that is for your car, because theya re different based on rear end ratio and tire size. Otherwise your speedo won't be accurate.

Yes, i'm talking about fifth. I was just wondering why one was bigger and tapered on the end facing the front of the trans. There are a few chips in the big one. I think i'm going to just reuse it. I never had any problem shifting into fifth.

Chips on the teeth won't cause problems with shifting. If the gear has chipped teeth I would replace it. Eventually the gear will fail. The chips have induced stress risers into the gear and weakened it.