Thae factory has started to send out new ladder chains for everyone who owns a 9000 series combine.The new ones are dipped in hot plastic so that it melts around the chain tightly and no dust or moisture can get in.The old ones only ran through a tube which was open to dust and moisture allowing the chain to rust and break and could let you fall if you leaned against it.The new ones aren't hard to replace,they connect to where the old ones do.