I found out that there is a unmachined area that the PG goes over and they want to make sure that is michined, also the spitter gears get machined also,this is why PG would rather do that themselves (the install), send yours ,for them to build it and send it back would be about 5 to 6 days,,, I may have a spare rear to donate as a core unit to be built and then send yous in for the next guy. jim