Welcome, but did you make any effort to look for an answer before you posted?
You told us it is a 4 cylinder, but you didn't give us a year. That would help.
You cannot use a V6 trans on a 4 cylinder car. The bell housing pattern does not match.
There are two types of MTX75 transmissions used on the Contour. The rod shift 95-97 and the cable shift 98-00. They are not interchangable.
Most of the stuff inside the different transmissions are interchangable. The biggest exceptions are the final drives (different ratio between the 4 cylinder and the V6) and the shift related stuff. Although I say most, it is not a sure bet that you will find everything inside one trans to repair another.
You're two best options at this point are to find a used wrecking yard trans that is from the same engine and in the same year range and to contact Terry Haines to rebuild yours.
Tony should be along in a few to provide you with contact information for Terry.