914 reconditioned gearbox sitting, how long is to long? Options

[Creamsicle New Zealand]

Hi all.
It's been a while since I last posted, still check in every day before starting work with a cup of coffee to see who's doing what, always interesting.

I have a question for the collective -

I have a fully reconditioned 914 gearbox waiting to be installed. Gearbox was reconditioned about 4 years ago. Reconditioner was a well-regarded gearbox expert (he built many reliable gearbox's for racing VW off roaders etc.) and has since passed away, huge loss for VW air-cooled folks as he was also a great engine rebuilder and a wealth of knowledge.

I imagine he would have used the correct procedures i.e. grease and oil to the gears etc. during the rebuild.

He told me not to fill the gear box with oil until installation. Not sure why.

Occasionally I turn the main shaft to ensure its still turn freely.

As its still waiting for install and I think it may be couple more years before it goes into car I'm wondering how long it could be left without gear box oil in it and if I should be doing anything in particular to ensure it remains good?
Thanks in advance for any input.
Cheers Steve

[mepstein]

I would fill it with some marvel mystery oil, turn the stub axles and then drain it before actual use. Doesn’t hurt to wipe down the outside with the same.