Just recently did my first swap everything went well. What I need help with is when I shift or try to shift into 3rd from 2nd when above 5/6k rpm it grinds really bad. I avoid using 3rd altogether but has anyone had same issue. Is it the gear or would it be the synchos. It's a hydro LS tranny and all other gears are just fine

 

probly the synchro man the slider isnt smoothly engaging because of it.

 

Anyone else have a thought on what it could be?

 

i'm gonna agree with syncro's as it's pretty much a common problem on these transmissions. u can first make sure you have the right amount of fluid, and even try replacing it with syncromesh from pennzoil. u need about 3 quarts. chances are that if it's really bad, you'll need 3rd syncro.