Ran into a huge issue with my 2004.5 sedan . Here's the story , my battery died so I had a friend jump start my car then the AT check light would flash once then stay on . The transmission went into fail safe mode and wont get out of 4th gear so it has a huge lag driving off from a stop . It jolts going into drive or reverse . Took my car to mechanic, to have my car diagnosed and they said the valve body needed to be replaced because the Tcm was throwing two codes u1000, p1757 front brake solenoid and p1754 input clutch solenoid. I Bought a good working valve body from an 05 sedan with same part numbers and had it installed there but the trans is still in fail safe mode with the same symptoms. Car is not throwing any codes on the ecm or Tcm . So I'm stumped on what the issue could be . Mechanics at carzone had no idea what was wrong with the car. I'm out 1k so far trying to fix this damn problem .
Done so many searching and can't seem to find any g35 related.
Anyone ever deal with this problem ? Thanks guys

 

Tcm might need reprogramming. I would look into that first