Longtime lurker first time poster. This forum rocks.

My '91 XJ has the AX15 gearbox and seems great except it grinds the synchros and won't go into gear when trying to directly downshift from 5th to 4th. Everything else is great including shifting up from 3rd to 4th. I've gotten in the habit when exiting the freeway, etc, to just, clutch in, shift through 3rd to 4th when leaving 5th to mitigate the issue. But in the back of my mind, I worry there is a total failure looming in my future that I'm just ignoring. I don't know enough about manual transmissions to know if failure is impending or if this is something I can live with for a couple years until I swap or stroke the engine.

Any wisdom from the Jeep sages?

Also, obligatory Jeep **** from the Pony Express trail last week: