Fordem, my engine is still sound and runs very reliably, given it had almost 200K miles on him back at that time. I'm right at 207K miles now and he is still going strong (minus the seal and throw out bearing issue which is now being corrected).
I don't know for certain, but I suspect the Olds was quite a bit heavier than my Tracker. There weren't any severe hills on the tow, just one long slope up grade and then down a sharp hill to the garage where it was being repaired. My mechanic friend was test driving it when it died and would not restart on him and left him stranded out on a country road. He had no one to assist him recover the car that day back at the shop so he called me as he occasionally does. He's a great guy and I always try to have his back when he needs an extra hand. I just towed him back to his garage for the repair.
I used my low range to tow it because, first, I didn't want to stress my clutch towing it several miles and second, I knew I wasn't going to be hitting any high speeds during the tow because of control safety issues during the tow.
I'm pretty sure I would have had difficulties towing it that far using high range, but I also didn't even try it.