A999 tranny same as 904?

The A-999 is a great transmission. The differences from a standard 904 are as follows..... 5 disc direct drum, 4 disc forward drum, 4 pinion planetaries instead of 3, and a lower 1st gearset. Some will argue that the 999 also came with a 4 disc direct drum, but they did not. If it has a 4 disc direct drum it is an a-998. All exterior dimensions are the same and all linkages will interchange.