Torque converter problems?

I'll throw out a guess.
Sounds like the shoulder on the band that the adjuster pushes on broke off the band.
With only 1000 miles I'd guess a cheap replacement went in.
You still have to pull the tranny to fix, but you might not need a complete rebuild, just a new band and gaskets. Check for metal, but you might luck out.
good luck

I respectfully inject this is not possible. Neither band will stop forward motion all together if broken. The front band is only for 2nd gear so it would still have 1st and 3rd with a broken front band. The rear band is mainly only for reverse so if it broke it would only loose reverse. I say mainly because the rear band does apply in manual low but it would still drive in 1st gear if broken. It just wouldn't provide extra holding power for the rear sprague to protect it under high stress.