Help trans?

[05chevy]

I have a buddy that is having trans problems nv4500 I think it is the 5th and reverse gears. Also has trouble of getring into third. Can I just replace the back two gears and be ok and the bearings all seem tight. Also what should I do about third gear?

bobby

 

[displacedtexan]

Third needs a new synchro.

I'd do em all and bearings while I was in there.