Ok, so here's the deal. I have an 04 g35c 5AT w/ 74,000 miles on it. I took it in recently to a trusted mechanic because my steering rack was leaking and i walked out being referred to a transmission shop because of a bad solenoid code(There was some slight stuttering). So after the rack was repaired, I took it to the tranny shop and they replaced the valve body. I did a search and saw that there was a TSB on the 06-07 valve bodies, so I figured that was the issue as well. So i drive out of the shop and everything is fine for the first 20 minutes or so, then I get on the expressway and decide to give it a little gas and the damn thing hits the rev limiter in 4th and won't shift into 5th. I then slow down and try to drive "normally;" however, the shifting seems way off. The shift from 1st to 2nd is good(aound 1500-2200 RPMs), from 2nd to third(1500-2200 RPMs) is good; but third to 4th there is a hesistation (shifts at 3,000-3,500 RPMS). It will redline if I am not careful. Using manumatic helps, but that is besides the point. The service tech said that there is a learning period, but i have driven the car for 5 days and have reset the ecu and it is still shifting that way. It feels like it doesn't know when to shift into 4th. Any ideas?

Update: So I was driving on the expressway and the tranny died. It wouldn't shift past 3rd and started shaking violently. I took it back to the shop and now they are talking about rebuilding it. It sounds to me like they screwed up the valve body install/ learning phase. It was running relatively smooth before I took it in. Why would replacing a valve body somehow destroy my clutch packs, if they were shifting fine before? I have looked around and there are not many instances of transmissions dying at 75k w/o going FI. I really don't know what to do, but it feels like I getting the short end of the stick here. Any ideas?