Somewhere on line, there is the original '63 Ray Brock story from HRM on the Transaxle, of which only about 20-25 were ever produced, with 14 going in production cars (6 wagons, 6 coupes, 2 mule cars) and a few spares.
It engaged with a clutch, but moved through the rest of the gears as an automatic. The genius move was to abut two Powerglide planetary units on a common housing, and route the power back and forth between fore and aft through a hollow pinion (!)
No accumulator so it shifted with a bang, but, it was by far the most sophisticated automatic of the time, and for some time after. Thanks to the power going back and forth to the planetary units (the article is great to explain how it worked) the ratio spread was about the same as a Super T10.
With a race on the high banks, in the rain, Goldie stayed up in the high groove where water wasn't pooling, and thanks to the GM wipers and ventilation system, he could see where he was going. Thanks to the SD, I don't think he had to let it all the way out to win. However, next day at the road course, the constant up and down shifting, the #50 was a DNF.
At the drags, it was very successful, the only car of the era in its class to have 50/50 weight distribution. The IRS would bite like mad - but as soon as the AFXs allowed an 8" tire - that was it. Most racers junked the PowerShift for a standard Pontiac 9.3" or cut them up for AWB projects. I'd need to recheck to see how many survive, it's not many. There are at least one stawag and one coupe that were restored to mint original condition hy Tom's friend Scott Tiemann, with fully functioning PowerShift transmissions. The latest resto was the $226,000 eBay dumpster rescue Tempest coupe, which uses the as-raced Pontiac 9.3" dropout live axle - the current owners of the original aluminum front end parts and rear transaxle were functionally holding the parts hostage, so Scott bypassed them both.
I'd have to dig to see how many of the 14 have been accounted for today.