That's the first I've ever heard of a GM trans with a Ford motor. Very interesting. It sound like the torque converter to me. I lost 4th gear once in my '96 Dodge. I was trying to get home so I just used 1st thru 3rd. Eventually I lost 3rd, after a few more miles I lost 2nd. Eventually lost 1st about 1 mile from home. It wouldn't move forward at all. I put it in reverse and that still worked. I backed it home the last mile.
Transmission guy said if I had just let it set after loosing 4th it would have been a much less expensive repair instead of an entire rebuild. Live and learn.
