I was ready to give up on my '84 vanagon when the beast would not go into
any forward gears after starting. It would go into reverse just fine, but
any drive gear sometimes took several minutes of high speed idling before
the gears would engage with a violent thunk. After putting  TransX in the
transmission fluid, it hasn't given me a problem since.

Can anybody explain this behavior?

How likely is it that my problem will reoccur soon. The vanagon has driven
fine for two months with the transX.

Justin