[jcp123]

Originally Posted by Hersbird

Some of these don't work exactly as you would expect. It is possible they automatically skip ship for you or use something like 2 different 2nd gear ratios depending on load. The "4 speed" dodge 545rfe. It had an extra gear added with just a software change on the 99 Grand Cherokee after they were built and sold. It didn't need a whole extra mechanical gear added as it basically was a 3 speed auto with a gear splitter. They should be able to with just software make it a 6 speed. So a 4 speed with a gear splitter can be an 8 speed. You can add a aftermarket gear splitter like the gear vendors overdrive and not just get an overdrive but split your other gears as well to get 6 speeds out of any old 3 speed auto.
No doubt it's more then just marketing as some of these cars are available with both the 6 speed or the 8 speed in otherwise identical configuration, the 8 speed always has a better city and Highway EPA rating.

That's why I like the old BW overdrive units. They're kind of an odd bird to operate but quite effective.