I posted this on another forum last year:
I recently replaced the steering box on my wife's '97 and while I've used various methods for removing the drop arm, mainly heat and hammering, this time I decided to do it "right", especially since I may rebuild the old box myself and didn't want to risk any damage.
After some research I found that the OTC6497 Ford Super-Duty Pitman Arm Puller fits & works perfectly.
A call to OTC tech support connected me with someone very helpful who got one of the pullers while I was on the phone and took measurements.
Others I looked at were too small and/or cheap).
This is the cheapest place I could find it.
OTC 6497 Front End - Puller
Very good customer service, with only minutes to spare before UPS came, they rushed my order to make the pickup that day.
Even with the puller, I had to place a 4ft pipe on the drop arm and stand on it and use my high-lift handle on my breaker bar to pull the arm.
This will work on 89-99 D1's
Maybe others, I'm not sure