1988 244 147K automatic transmission

One of the 240's has developed a new noise.

Perhaps insignificant but I will mention that this started after a three day period of torrental rainfall.

There is a noise that can only be described as SCREECHING at start up. It is not there while cranking but sounds off after releasing the key once the engine is running.

During the wet period it was doing it pretty much at every startup. Now a week later it only does it on cold morning startups. The duration of the sound is a second or less.

I have a feeling it is associated with the starter pinion. Almost as though as the engine speed increases at startup the pinion gear is driven at a faster RPM just prior to disengagement.

Has anyone experienced this before and what did you find to be the problem? Is there some portion of the assembly that I might try to lube or is this just normal wear requiring replacement? Based on my experiences it seems to be relatively low mileage for a needed replacement.

I realize that no matter the cause or the cure I will probably soon be removing the starter and that makes me unhappy....

Randy