You have come to the right place. We have a number of members with knowledge of Ransomes crawlers, including one that can supply spare parts.
I would suggest you start by getting a copy of the parts list and owners manual.
Photos always help with identifying items or problems.
Welcome. I am as far as known the only person with any new Ransomes MG spares but it is only my hobby. will need to establish which version of the crawler you have and I can send copies of manuals and parts books so please email me njarrett@btinternet.com
Neil