Firstfives.org

So I have a slight vibration at around 2500revs and what sounds like someone taping the drive shaft tunnel with a block of wood at all speeds. I checked the center support bearing and guibo and they "look" fine - in fact, they look almost new. There is a sliiiiiiiiiiiiight amount of "wiggle" in the u-joint but very little. The knocking sound is the most annoying as it speeds up or slows down with speed. I checked around the shaft and couldn't find any physical interference with the shaft. Could this be a pre-load problem with the center bearing? I'm stumped!

It shouldn't be, but it might be. If everything is perfectly balanced and no wear or binding, preload of the center bearing isn't really needed. However as the car and components age, it is. Preloading just stiffens it so it doesn't move around as much. If it's bad, another kludge is to glue a piece of fuel line in the hollow to stiffen it up even more.

Thanks!

I'm going to look into the pre-load then.