I have a quick question about my 2000ls1. My t56 was doing great until i let one of my buddies make a pass in it. And now it pops out of 4th everytime i shift to it and have to actually shift into 4th twice if you know what i mean. It was not doing this before he drove it and he shifts really hard so I am thinking the 3/4 shift fork is bent. Also last night it stuck in third when i shifted hard. Any ideas?

I have a 3/4 shift fork from a lt1 car that I am going to install f they are the same as the ls1.
I read somewhere that it may be the keys.

 

3-4 shift fork