[quote=spdrun]Did it damage the engine, or was it a case of empty, flush, refill, refill again, keep fingers crossed? Interestingly, several cars that I’ve owned specified 10W30 oil in the gearbox instead of GL4 or ATF.[/quote]

I don’t remember. I think the person noticed the color of the fluid not being correct, and then had it towed somewhere else and drained and refilled it.