Believe it or not, good used factory cast aluminum accumulators are not as easy to find as they use to be, especially if you need to have a regular supply of them. Chrysler hasn't put them in anything since the 80's (over 30 years). No Cummins powered truck came with the cast aluminum accumulator, no overdrive transmission ever came with the cast aluminum accumulator. The switch to plastic happened before either of those even existed. There is a huge market for people that are building transmissions for Cummins trucks and people building performance overdrive gas transmissions. Most shops that specialize in rebuilding those transmissions wouldn't even reuse the plastic accumulator in a completely stock rebuild. If someone building a transmission thinks that 45 bucks is too "pricey" for a part that is readily available and completely solves a problem that does exist, well, I guess I don't really have an answer for that.