It sounds as if you have slop in the shifter shaft along the way; so, all your side to side movement is not being transmitted to the ZF. The likely culprit, if your u-joints are sound and your connections are tight, is in the mounting of your gearshift lever to the shifter shaft. The bushings may be worn and your motion not fully translated. The whole unit is easily removed from the car. It probably wouldn't hurt anyway as a lot of crap collects down there over time. I don't remember the mechanism exactly; however, it seems to me we remedied similar worn parts with a larger pin from Ace hardware and shims in the past.
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