My part "was" called: differential sungear thurst bearing assembly. Thankfully the magnet is close to the drainback hole from the diff. housing and captured most of the debris, the filter stopepd the rest. The reapir was at 157k, but I think it had been broken a long time because the picture was taken the first time I did the fluid change to this car at 143k. The only thing that led me to investigate this was a noise on de-accell. Original transmission now has 171k and still going strong.