??need ideas..won't shift..??
 

I have a 2000 TA 4l60E with a vig 3600 stall and bigger trans cooler. my car will shift fine from 1-2 up to 25 mph, but it won't shift into 3rd or 4th, the rpms just shoot up and sit at redline. I got a code for the shift solenoid b ckt stuck off/performance but I already replaced both shift solenoids(1-2,2-3) and the problem is still there. And I did have the car tuned a while back for the stall. I also got a o2 sensor code for an exhaust leak but dont think that matters.Any ideas/ opinions are greatly appreciated.

if the car just revs "neutrals" where the 2-3 shift should be you have a 3-4 clutch failure :( a mechanical failure.

How much does that generally cost parts/labor.

Most shops will not just replace the 3-4 set for warranty reasons, You are likely looking at a complete rebuild or replacing the transmission. I have no idea what a shop would charge just to replace that if you could find one that would:(