Prop shaft won't turn in neutral

[drlizard]

Greetings, 3JH4E with Kanzaki KM35P transmission(1200 hrs), PSS shaft seal, fixed 3 blade prop. Ran the engine after sitting 4 months. Ran in gear to get up to temp, no issues, ran in reverse also no issues, then shifted a couple more times(always deliberately over lifetime of gear) and have squealing now in forward and reverse, none in neutral. Tried to turn propshaft by hand, very tight, couldn't budge. Wife dove on prop, prop is clear. Changed transmission oil next day, squealing less but still present in both directions, put magnets against old oil in jar to see if any metal was in old oil(haven't checked yet). While shifting after the oil change, there seems to be a little resistance just past neutral when going forward sometimes, none in reverse. Shaft turns when in either gear. What's the next logical check to do? Unfortunately I have a canoe stern, and with increased exhaust size it's very tough to get at coupler and shaft seal. Hard to tell where squealing is coming from by ear. Could it be motor mounts putting pressure on cutlass bearing? How does one check mounts? Shifter lever looks to be fully engaging in both directions. Seemed to be a definite event, not a gradual change. Trying to pin down cause before hauling out later this year, will be going back to shaft log when out due to poor access to PSS seal.

[SailingHarmonie]

If a mechanical inspection doesn't show an obvious problem with the motor mounts, the only thing to do is to check the shaft alignment.

I think it unlikely the problem is with the transmission, it seems symptoms would be different, not so much "squealing" more "grinding". Although if the alignment is far out of spec, transmission seal and bearing issues will not be long in the future.

[GordMay]

If loosening the packing gland doesn't fix things, recommend you pull the bolts connecting the shaft coupling to the transmission.
This will tell which end your problem resides: shaft end, or transmission end.

[skipperpete]

Here’s a possibility from an old thread, the symptoms you describe are fairly well known in some parts of the world.

[drlizard]

Post haulout follow up: Motor mounts went bad, and in doing so bent the propshaft, which then caused the cutlass bearing to spin in the stern tube making the offending noise. New motor mounts, new propshaft, and new cutlass bearing with improved mounting. Transmission and all else fine now.