Excess fluid in tailshaft

Thanks for the tips guys. I suspect that the slip yoke is worn. I have a used one on now that was better than the original one. That got rid of my vibration last year. I was also filling to the drain plug level; not 3/4" below. I will try that too. A new slip yoke might be an issue though; unless it is the same as a 904. I am going to stick with ATF for lube though. The trans shifts nicely with it; or as nicely as a 903 can shift. Perhaps I should just change to a 230, and make the necessary linkage/driveshaft changes. Maybe someday.

This car is one of those unrestored ones that is kinda beat up, but not too horrible (by Michigan standards), and if I restored it, I think I'd ruin it. :)