Your 3-4 clutch is breathing it's last. There's a mile of clearance it there. Your 2nd gear servo travel is probably on the excessive side as well. Both of these will give you a nasty flare on the 2-3 shift.
There are a TON of things besides an overhaul kit that need to go into a 4L60E to build it properly. If you've never done one, I'd think it over carefully. It's not a beginner transmission. Skip the shift kit, too. No need for that crap in a 4L60E...
You can search through this site and find a ton of information about proper setups. I know that between Frank Cahall and myself (and others), we've offered up a bunch of information on here...
There are a TON of things besides an overhaul kit that need to go into a 4L60E to build it properly. If you've never done one, I'd think it over carefully. It's not a beginner transmission. Skip the shift kit, too. No need for that crap in a 4L60E...
You can search through this site and find a ton of information about proper setups. I know that between Frank Cahall and myself (and others), we've offered up a bunch of information on here...