$150, cool, order me one will ya.
Since they replaced what looked like ~1/8-3/16" thick roller thrust bearing unit with a ~ 1/4-5/16" composite washer(4.9mm >3/16" thicker than original part), i am thinking the only real critical tolerance is going to be the diameter. Need a temperature and oil tolerant composite or light metal(aluminum or bronze perhaps) since the adjacent surfaces appear to be steel. Allison probably settled on composite as it was cheaper to manufacture... I could probably turn one of these out in aluminum on the lathe in an hour or so?
That is I believe the point of the composite, The original was getting hammered either when the P6 engages or disengages(1st gear) until failure.. The composite can wear or even fail and it should do no serious damage to the rest of the transmission unlike the hardened rollers and cage of the original thrust bearing assembly that chewed their way thru the C6 clutch pack and aluminum housing in this failure example...
I'd be happy to, I didn't keep the receipt unfortunately so I'm not sure if it was the same p/n. It was the composite bearing though. I was surprised by the thickness change and it threw me for a bit of a loop during install.
I'd try some other dealers, it is possible they changed the price recently but seems doubtful.
Using another material, especially polymers is very complicated. The wear characteristics, strength, temp tolerance, creep, CTE. This was a huge challenge for Allison engineers so I wouldn't even bother trying to reengineer that wheel.