I recall the mast replacement was pretty easy.
Most of the time in my case was invested in cleaning and roughing things up, because I needed to epoxy a broken plastic part (the part that engages the shock absorbing spring-not available separately).

The old grease was all hardened up and done. Fortunately, the plastic gears were still in good shape. I replaced the drive belt (cheap) for good measure, though it appeared to be fine.

I would suggest a thorough cleaning, which may require some extra disassembly.

I lubed everything with silicone grease (NOT silicone spray which is very different), available in tubes at most auto parts stores. I feel this is the best stuff for plastic parts.

Best of luck.

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1986 300E 5-Speed 240k mi.