Working on 16 year old sons 1999 Z28 trans issue. Ok when I bought the car I knew it had a week trans (During test drive it would shift out of OD to Drive and back) Guy knock 500 off price of car. I drove it this week end and now no 3rd or 4th gear. I have been reading up on how weak the 4L60e is and can't decide if I need to do the swap now or later. We will be beating on it at the track next summer. What do you guys think? Sould I beef up the 4L60e or swap for 4L80e and what are the benifets either way. Me and my son will be pulling and installing the trans just have to pay for the build.

 

Should have did the search before I posted, been reading old post and sticky for the last two hours and leaning towards rebuilding the 4L60E for now. Did not know it was that much trouble to swap out. Thanks LS1 TECH GUYS

 

Yes, it is non-trivial to swap to a 4L80E. A well-built 4L60E, e.g. from some Sponsors, will easily handle 500HP for many years and many track runs.
Are you planning to get a rebuilt trans from a sponsor, have a local shop rebuild it or do it yourself?

 

Yes the swap to a 4L80E is not a trivial swap and not needed at your power levels IMO

 

My son and I will be taking the trans out Friday night. Old dragracing buddy will be rebuilding it for us. Said he was going to add heavy duty stuff and 2 more discs with better sun sheild or something like that. I been knowing him for about 25 years so just told him what ever he thought it needed. He was against the 4L80e switch from the start said he could beef the 4L60e up. We will be out of parts cost and a little labor cost for my buddies time.

 

While everything is out Id order a new converter.

 

60 is the right way to go.

 

I was thinking about going with a 4L80 but the gearing isn't desirable for my power level. I'd only swap to an 80e with big power as the 60e has a more aggressive 1st gear.

You're making the right choice with the 60e. Lighten the car up and it'll be even better.

 

This. Grab a Yank or Circle D (quality brand is key for drivability and results) 3,000+ rpm converter, and get the car tuned when its put back together. Tuning, a couple bolt-ons, and quality stall alone would be worth around a full second in your 1/4 mile time.