DWRogers, welcome to the forum and good luck with the new 8N!
As said, there is a lot of info in the archives but here is a quick
summary of what I've read. This is off the top of my head, so I
may miss some. BTW, I have not tried to run a tiller with mine.
The ground speed of the N series is what people are saying is
too high to run a tiller. Even in first it just doesn't let the tiller
dig in and do its job, specially in un-worked or hard soil types.
Enter the auxiliary transmissions. There are many types that people
may call "Hi-Lo" setups. The most common is the Sherman step-up
transmission which gives you the normal N speeds plus a faster
range. Not what you want for a tiller. PTO speed is increased too.
Then there is a Sherman step-down, which gives you the normal
range plus a slower ground speed range but also slows the PTO.
There's a Sherman combo that gives you all three ranges, PTO speed
is affected as with any auxiliary that goes in front of the trans.
Others, like the Howard, go behind the original transmission so
they can slow the ground speed and not affect the PTO speed.
John Smith has an entire section on the many types of auxiliary
transmission. It's much easier to find and look through!
Here's a
LINK.