A855 - 5 Speed

Why are there problems with the 855?? Trick question it is.

The manufacturing of gears is not simple, it requires a series of checks and balances to ensure all the parts work together no matter when the part was made. Dimensional metrology comes to mind along with a master gear set. All this costs money and requires precision metrology equipment $$$$$ to measure the complex parts. Is there a master gear set? Due to the problems I highly doubt the components are correctly manufactured/checked for the correct dimesions or a master gear set exisits. The big 3 never had to install a trans in a car to see if it works...

New transmissions that make noise, won't shift/go into gear - produces a lot of metal in the gear oil. I had problems within 50 miles with 2 new 4sp aluminum overdrives - the first one locked up within 50 miles and the car had to be towed from a bad place- the second one - had 4th gear noise that from mile zero took a while 500-1000 miles or so to go away which was quite annoying considering the money spent. I changed the trans lube on a regular basis until the noise stopped. I was told that is normal....

Metrology is the scientific study of measurement
https://www.gleason.com/en/products/tools/inspection/master-gears/master-gear-tools