I have six NOS Standard LX101 from the early to mid 80s based on the Transistor Dates and Original Boxes Made In The USA with QR Dates
Some are 5 pin , some are 4 pin
Two of them same as yours pictured , the directions stuck to the black epoxy compound right in the box
Many threads on these running just fine with the compound dripping down the firewall - Factory Chrysler - Aftermarket
Some of stated they are getting ready to fail or getting hot from grounds / ohms / resistance
My answer , explain brand new in the box never installed and leaking
Bottom Line - Age Age Age / Heat Humidity / Failing compound
I have used a heat gun , scrape - But of course you have to risk the main board