OK, so the two new axles are in and the car has been running fine for the last
month or so. BUT, just yesterday, as I was taking off from a light, the transmission
slipped out of first into neutral as I accelerated from a stop.

This happens only in first and the car shifts fine otherwise.

I attempted to adjust the shift linkage from inside but that didn't seem to help.

I can hold the shift lever into first and keep it in gear until it's time to shift but
what am I looking at to fix the problem?

thanks,
john

(owning a 914= )

Sounds like the engine mounts have broken. Easy to replace even with the engine in the car.