S.C...what David said, then the following: I worked for 6+ years in the parts business. We sold Lucas additives. All seemed to work well and, while the Auto trans. additive seemed to help with leaks, never really saw that with the man. trans. additive...it mainly helped with those worn, whining, growling noises. Further, this stuff is THICK. My guess is that if you had a full size truck that had a rear end on its last leg, be my guest. However, because it is so thick, I don't know that a cold engine coupled with a cold transaxle would be able to hold an idle in the winter time if you used it in a bug.
How thick is it? If you've ever used STP oil additive, that's pretty close.
Stick with 80w90 gear oil, like bugtech said.
About that noise, if your relay is crapping out, they can sometimes buzz when you hit the turn signal. try tapping the relay and see if the noise goes away and the blinkers start blinking. Also, if your turn signal lights come on but don't flash, this could also sometimes be caused by a corroded bulb base/socket.
...Or a bad switch...or a bad ground....or a bad connection....
Try twisting the fuses in the panel...don't remove them, just turn them on the little prongs they rest on. I've fixed a bunch of weird lighting stuff over the years with that one...they build up corrosion on the tip of the fuse and by rotating the fuse, you polish the little corroded bumps off of them. Good luck.
