Can I use two winches at once? One pulling while the other releasing?

Using two winches as described, one wining in and one wining out is not recommended, this could and likely would have the following problems.

1. Yes the winch is geared the same, but there could be a slight difference in the motor speed.  One motor could be wound tighter and would spin at a different speed than the other causing a pulling force or a cable slack between the winches, depending on the direction.
2. The number of cable layer on the drum also would cause a difference in cable payout or take up. 
• The drum paying out the cable starts full and larger in diameter, more inches of cable per drum rotation will be paying out.
• The drum taking up the cable is starting empty and smaller in diameter, less inches of cable will be taken up or retrieve per drum rotation.
• Trying to use two winches in series will never be a direct one to one payout and take up per drum rotation.
3. What is the application?
• Opening a gate?
• Pulling a trolly cart up and down a track?

Winches should never be used to move live cargo.

Winch should never be used for overhead lifting.