Dave's right as usual,
I checked the AT 540, 543, 545 manual I have here and they all should have PTO provisions. Same goes for MT 640, 643, 650, and 653 according to the service manual

I also checked the sales literature I have for the new electronic Allison's, and a model 3,000 or 4,000 was/is available with a PTO delete option.

The transmission in question should be an old style, and therefore would (should) have the PTO option standard.

Grigg

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
---All pictures---
"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-