my ax5 is sh*t... syncro's in all 5 are done, my buddy just offered me his AX5 but it is internal.... I know nothing about the benefits of either, so if someone can explain that would be great.
otherwise if its wrong to go to internal or worse... then i will just keep grinding them since its a trail rig
Take the bellhousing & front bearing retainer off of your external slave unit, install them on the internal slave. Swap transmissions.
You now have a newer transmission that doesn't grind, without having to swap to the inferior (and stupid) internal/concentric slave cylinder setup. It was a dumb idea when Mazda did it, it stayed a dumb idea when Ford did it, and the story does not improve with telling.
There's much greater difficulty in getting the concentric slave to seal than the conventional slave, and to replace the slave you must remove the transmission!
Since it's going to be relatively easy for you to change over the transmission to accept the current hydraulics, and you'll have both units in front of you, there's no reason to not do it.
Simply swap the bellhousing & associated parts over to the replacement box. With both of them on the bench in front of you, it's easy - just remove the parts that are different on the box you've taken out and put them on the replacement.
It's also much cheaper than having to swap hydraulics anyhow - which is what you'd be looking at.
To explain it to you why you don't want an internal. Because the slave on an internal is inside the bell houseing,and when it goes bad,as they often do, you have to pull the trans to replace it. On yours is right on the out side. Take the trans and swap it for yours, but just the trans.
Make sure you look at the new tranny and the old tranny side-by-side to see that everything matches. When I swapped to a newer AX15 from an old one to swap from internal to an external slave, I found out the external slave had a smaller pilot than the internal. There might be a trip to make some custom parts at the machine shop, but it would be worth it.