2006 Mercury 90 Optimax - Very Stiff Shifting

Howdy All

Shifting gone very stiff on the last outing (yesterday)
Throttling back from high revs in forward was tight.
Adjusted the throttle friction and made no difference.
Shifting into reverse by the end of the day was really really hard (very nearly hit the dock coming in)
Just engaged reverse but wouldn't rev up.

First off its not the cables or the remote - already pulled them apart and isolated them.
When the cables are disconnected at the engine, the cables and remote move ok, no binding etc

Checked the shifter on the side of the block and... cracks.. so todays trip is cancelled :(

Given the cracks are in the slide I would assume its something downstream into the gearbox binding up? ie the cables can provide enough pressure to crack the slide.

When the cables are disconnected its still really stiff to come back from fwd. (Goes in fwd ok.ish)
Was using 2 ring spanners top and bottom to isolate any twisting of the slide but was still very tight.
Was spinning prop with foot to ensure the gearbox was moving against it - ie not blocked by gears meshing.

I cant find any schematics of what the shift slide is attached too other than its under the engine block and tucked away.

Anyone got any pointers before I let the mechanics at it?

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