I understand “do what you have to”, but you need to be aware of the consequences… In simple terms ( and not to be sarcastic), think of a grinding wheel spinning, and then pushing a screwdriver against the side of the wheel. As long as you apply force, the grinding wheel will wear down the screwdriver. The collars and the forks in a trans are something of the same, but both wear each other down. In a perfect setup, the syncros will lock the collar in position with detents, and detents on the shaft for the shifting forks hold them in position where they only come in contact during the actual shifting, any other time, they don’t touch….
What I would recommend trying is to disconnect the shifter at the ball and socket on the t case. By hand, then shift the t case into hi range, then in a safe,flat area , drive the Pinz with the shifter disconnected. Try driving hard and soft, heavy and acceleration and shifting. If the problem is inside the t case, it will probably pop out of gear rather soon…But be sure you’re driving in an area where it would be safe to coast and not have the engine or trans to power you if it does pop out of gear and can stop safely and chock the wheels… so no hills. Have someone with you to chock the wheels while your holding the brakes.
If the t case does not go to neutral, it could still be only a cable adjustment… but also shift the t case to low range and try the same test…I drove my 712 for a week before I repair the shifter cable on it.
Also, drain the t case into a pan and check for 'Yukon gold'... bright shiny shreds of metal in it
Now my disclaimer: this post exceeds my 3 finger limit and therefore not proof read
