Which axis (or both) is the jitter occurring in?
I have a 10" f/6.6 tube (67 lb in total) mounted on an Astrola mount with 1.5" axis, perhaps just a bit longer and a little heavier than yours? I see about a 3s settling time after moving the tube and that is all, even at x480. Wind will disturb my telescope but it settles just as fast once the gusts stop.
Try the following:
--(1) first make sure your telescope is balanced, both in RA and Dec. To do this:
(i) loosen both axes completely
(ii) first the Dec axis: position the RA axis so the Dec axis rotates in the vertical
(iii) tighten the RA axis so it doesn't move
(iv) rotate the telescope tube in the DEC axis to horizontal. Even with the Dec axis completely unlocked, the telescope tube
+intermediate-weight eyepiece should balance essentially perfectly. If not, you must add weight on the appropriate
tube end. Lead fishing weights drilled for a small bolt work nicely, BTW, and can be mounted on the inside end of
(v) next the RA axis: position the telescope to point along the polar axis, tighten the Dec lock, and completely loosen the
RA lock. Move the telescope so that the Dec axis is horizontal,
(vi) you guessed it--the telescope should balance about the RA axis. If not, loosen the counterweight set screw and slide
the counterweight to balance, then retighten the set screw and retaining locking collar (I am assuming everything
works and is not gummed up by rust), and
(vii) I am ignoring the radial balance (rotation along the tube axis). I assume this isn't too far out of balance. If it is, weights
opposite the "heavy" portion of the tube (usually a counterweight mounted on the outside, and a slider is nice
to accommodate differing eyepiece weights, see (iv)).
(2) if (1) doesn't work, what are the conditions of the bearings? Is the motion utterly smooth (it should be)? Is there "play" in either axis when you attempt to wiggle them? Does either axis slip longitudinally in its bearings? The answer to the preceding two questions s/b "no." If the motion isn't smooth, you may either need to grease the bearings or replace them. If "wiggle" in any dimension is detected, you have a problem that you'll need to disassemble the shaft and bearings from the housing to diagnose: 'could be bad or rusty bearings, 'could be play between the bearings and the housing(s), 'could be the shaft slipping in the bearings. The first is the most likely,
(3) It doesn't appear you have the Cave Dec drive so it can't be the Dec (similar to the RA gear) ring gear clutch.
Let us know.