Glad you found your squeak.

While the steering damper may make the steering feel heavier, its main function is to dampen out side to side oscillations. Sometimes in older vehicles, especially those with solid axles, the front wheels will give each other enough feedback to start oscillating. This results in the steering wheel shimmying in your hand. It peaks at one speed where tire rpm matches the resonant frequency specific to that vehicle and can get quite violent. The damper stops all that silliness before it can get started. Assuming no significant play in all the joints, bushings, tie rod ends, ad infinitum.

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Norm in NJ
Next oil change at 230,000miles