I didn't suggest a Watson because you were so sure it was a GM unit with casting numbers and all.
And I'd not seen a direct mounted auxiliary like it of any sort that old. Spicer did later have some very direct mounted ones making what they called a "compound" transmission.

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
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-