My G37 Coupe Second Gear grinds all the time I down shift at high rpms the gear goes in but grinds crazy and then it goes. and it also always grinds when i burnout i start first gear and try to pop it in second grinds crazy then it goes in to gear. How can i Fix this? I'm worried so my transmission doesn't brake soon because of this. Maybe Change my Trany oil you guys think it will Help?

 

Sounds like 2nd gear synchro is almost gone. You're wrecking the gear everytime you grind it.

Time to yank the transmission and repair. The longer you wait, more metal shavings are ending up in the sump with the pontential to do damage to the rest of the trans.

 

About how much will it cost me to repair that?

 

Not something I'd recommend you try yourself. I'd hazard a guess of a couple of grand to have a shop repair or maybe twice that for a used trans.