Been years since I worked on one- RH thread yes?
The only left-hand thread on the AMC gearbox is the big nut that holds the sprocket onto the Sleeve gear shaft. It sits outside the gearbox behind the clutch and primary case.
All the threads inside the gearbox are right handers.
Thanks so many years since i did one, still got my thin box spanner for inner case nuts that i spark eroded from solid bar 40 years ago! I also made one for the sprocket nut that had a hole for the clutch thread to come through and the clutch nut lightly screwed on, no more slipping off the sprocket nut, just got to find it!!!