91 Ranger auto trans using fluid

[88 XLT Ranger]

Question?

My friend has a 91 Ranger its an automatic trans it uses one quart of trans fluid every three weeks. He said it dont leak a drop on the driveway and he dont see any leaks under or around the trans. Why would it use trans fluid like that? where would it be going?

 

[exbass94]

A bad vacuum modulator would let ATF get sucked into the engine and burned.

 

[88 XLT Ranger]

A bad vacuum modulator would let ATF get sucked into the engine and burned.

Thank You!

I wil let him know so he can get it fixed