No reverse? Hmmmm...rev drum not holding pressure? Well, there is a band that remains stationary and it's primary job is to hold the rev drum/sun gear after it is adjusted (no servo action). The adjustment is on the top/driver side of the body of the trans. It is an allen set screw/lock nut deal. If the tow truck is coming I'd personally tighten that set screw down A LITTLE at a time and see what happens. That band adj is only like 4.3ft. lbs. Just a thought...