Subject: 95 Galant Auto Tranny Problem
Question:

My Galant can shift in lower gears with no problems. However, when it goes pass 30-40 Mph the RPM revs high and the tranny will not catch. If I turn off the overdrive then the car will run fine but the RPM is higher. I brought the car into a tranmission shop and they told me my fourth gear is gone. The trans sometimes make a loud thud when it's cold when driving.  

Answer: Do,
If your 4th gear is gone, your car will have problems getting above 40 MPH. The mechanic you brought your car has most likely diagnosed your problem correctly. The only way to know the extent of the damage will be to open the tranny and inspect it thoroughly. Get an estimate on a repair and then ask if it would be less expensive buy a rebuilt transmission. Sometimes you'll have money in labor costs.
Good luck!