Not great news
I don't like the word squealing. I had a 123 chassis blower motor that squealed and as a temp fix I removed it and cleaned all the motor bearing surfaces and relubed. It's doing fine but the 300E has a dual shaft motor as compared to the 123 and they are more of a pain to pull out that if I were doing it I would just replace the motor while I was in there. If the sound hasn't gotten to the point where the motor stops or blows a fuse I would ride it out until it dies before digging into the dash where it's located. I think O'reilly had this part for like $55.00 not bad at all but there is a lot of labor to getting the old one out.
"Tell me and I will listen, Teach me and I will learn, Show me and I will accomplish, Involve me and I will succeed."
'84 300SD 256,000 Gold on Brown (Mileage Award)
'86 300E 246,000 Blue on Tan