Squeaking might be lubrication or it might be excessive wear (part 24, and the inner sleeve of part 22 in the diagram above). As stated above, if the teeth are ok, disassemble, clean, and inspect the upper wheel and bushings. If worn, and you want to keep this style, they are available on ebay. If wear is not bad, lube and reassemble.
To all: is there a go-to good rear derailleur for use with friction shifting for use in a replacement in such situations?
Last edited by WizardOfBoz; 12-10-19 at 02:58 PM.