I had one in my 57 GMC for many years. 5 years ago the fan motor started dragging really bad so I ordered a new fan motor. Before I got it installed my truck was T-boned, rolled and totaled. Still have the motor in an un-opened box. I'm pretty sure all the Old Air units of the day (mine was installed in 1998) used the same 3 speed, reversible motor. If you'd like a free spare motor let me know.
