1948 JD M single vs dual Touch-O-Matic questions

[ThreeEdwardsM]

I have a 1948 John Deere M with the single Touch-O-Matic lever. The Model M operator’s manual shows the single lever, but the MI manual describes the dual Touch-O-Matic setup where the right and left levers can be operated independently or together.

I’m trying to learn what Deere intended here.

Questions:

• Was single Touch-O-Matic standard on early M tractors?
• Which M-family tractors commonly had dual Touch-O-Matic?
• What implements required/benefitted from the dual setup?
• Was dual mainly for cultivators or other integral Quick-Tatch equipment?
• How hard is it to convert a single-lever M to dual?
• Does that require a different hydraulic unit, or just the missing valve/linkage/lever parts?

My tractor appears very original, so I’m not assuming anything is missing. I’m trying to understand the history and the practical use of each setup.

Any photos, parts-book references, or firsthand experience would be appreciated.

 

[JD60Standard]

I haven’t been around a lot of M’s, but I believe the single Touch O Matic was on the standard M’s and the dual Touch O Matic was on the MT and MI models. To convert the single Touch O Matic to a dual I would assume that the entire rock shaft assembly (Touch O Matic) would have to changed.