so i just bought this 97 civ wit 99 ls motor and tranny.. has a skunk2 shorty in it and supposedly other tranny work but im told it was all fine and just stopped going into 3rd.. just wondering if you guys had any ideas why and if its an easy fix.. also is it something i could do myself. thanks

 

they prob lied to you, and dont know how to shift right and f'd up the syncro. you can drop the trans and split it and buy parts and fix it, or you can drop it and buy another trans and install it
and be done.
also just curious what else they lied about, look on the head just above the exhaust manifold and it will have a year made stamp. whats the number?

 

Does it grind or just won't go into third even with the engine shut off? It's possible it's not a synchro, but you're in for a tranny rebuild anyway. Do it yourself...transmissions are fascinating. Replace the 2nd and 3rd gear synchros and input shaft bearings while you're in there. Anything else that looks worn as well, but those are a must.