If it is ok going straight, likely its the u-joints.

Checking it with the drive removed, hold the end of the spline (spline in
palm, thumb pointing to u-joints) and give it a twist to load the bearings
tight, then, exercise the bearings by drawing a circle. If it feels smooth,
you're ok, chances are you'll feel the roughness - feels like rollers riding
over small ridges, a sort of sliding over a washboard effect. If you do a
90 movement one way then the next 90 degree direction, you won't feel
anything.

Tan PS


"doug" wrote in message
...
Is there any way to tell the difference between gimbal bearing or
universal
joint failure. At the end of last season my boat (1984 bayliner,305, volvo
280) started to vibrate when I made turns hard to port or starboard or
even
when in the slip at low rpm it still had the vibrations when I turned the
wheel hard one way or the other.At top speed going straight it was smooth
as
silk.I appreciate any help you can give.
Thanks, Dugb