I have a shift shock problem on a 2005 auto 3.2 Mitsubishi Pajero. The diagnostic testing said I had a "gearbox failure". The gearbox, transfer box, and torque converter were replaced, but the problem persists. The newest diagnosis is “torque converter fault". The vehicle seems to brake and slow, and then slams into gear. It is worse from 1st to 2nd and then into 3rd. Not too bad into 4th and 5th. We also had all the diff mountings replaced, as this was a suggested solution, but no such luck. The vehicle has an extreme amount of power and once through the gears drives like a dream. I really don't want to scrap the vehicle, but am at a loss on this one. I can't afford to waste any more money on this problem. I have to get it right this time.
Take it to a Mitsubishi dealer, or a reputable automatic transmission specialist to have it checked. It could be the computer controlling the auto, but you need a specialist to check it for you.