heavy vibration in reverse gear Volvo D1-30 and 130s sail drive

[borvaprops]

Hi guys, looking for some insight here Bavaria 33 2007 engine has 800 hours since new.  I just had my boat out of the water to replace anodes and put a fresh coat of antifouling on the hull.  Boat back in the water behaved jus fine until a few days later and now I have massive vibration on reverse.  Propeller is three years (3 bladed folding prop volvo) no maintenance done on sail drive recently. 
I was backing into my berth as usual and had to quick change from reverse into fwd gear as a person on a kayak decided it wanted to be crossing behind me as I was docking.  Long story short, massive vibration after quick move from Rev into Fwd gear.  I'm thinking the rubber on the damper plate (volvo pn 22026428) were damaged by the sudden movement from Rev to Fwd? Has anyone experienced this issue? If that's the issue I will need to split engine from sail drive to access these rubber cushions.  I'm assuming I can do this in the water since I will not be "touching" the sail drive?

Thanks for all the comments

[Yngmar]

If it's only in reverse, it cannot be the damper plate, which always spins in the same direction. It must be aft of the reverse gear. Given that it's happened right after an anode change, it's quite possibly just a loose saildrive anode, or even the prop, although you say you didn't touch that (did you do it yourself and thus know for sure?).

[borvaprops]

I dove on the prop and checked everything, anodes and bolts all tight nothing lose there.  It was all done by myself.  Vibration is heavy in reverse but present also in fwd gear but much more subtle. 

[JEN-et-ROSS]

If the Volvo prop folds and unfolds normally, and each of the blades gears are meshing as they should, then I can't see it being an issue with the prop...
And as already pointed out it can't be the damper plate for the reasons stated..
That only leaves the bit in-between, the gearbox, is there damage to the reverse gear, missing tooth or such.....??