F9 drive issue

[mechanic]

OK as per my other thread I have a F9 locomotive with a stripped drive that made pressing my 2-8-0 into service necessary. I've looked at the parts diagram on this site and the parts that are needed on my F9 are the white plastic worm gears. Part # 9903. I've talked to Bachmann and parts aren't available separately you have to buy the whole truck assy part# 9906. Unfortunately they aren't in stock and no delivery date known so I'm wondering if anyone knows of a aftermarket source for the 2 plastic worm gears Bach man uses in their F9's ? thanks in advance
Eric