Hopefully someone can point me in the right direction here...

Older Chris Craft center console with Chevy 350 5.7L V8, engine is believed to be 80's vintage. Do not know transmission type. Boat is mid 70's vintage.

Pulled boat for winterization last fall, no issues. In anticipation of unwinterizing and launching last week, had prop refurbished and I reinstalled it. Boat fired right up. Normally wouldn't put in gear while out of water but due to prop install, I engaged forward and reverse for very short period..

In forward at lowest RPM, noticable grumbling/knocking which resolves with more RPM
In Reverse grumbling/knocking/grinding..
Checked fluid - was low - added fluid to proper fill level
Dropped boat in water, forward fine - reverse still knocking/jumping (not sure what to call it)
Ran to slip at 3200 RPM - forward sounds fine (very slight whine when pushed just into forward)
Docking - when going into reverse, still sounds horrible...

withdrew all fluid - was dark but no sign of metal filings...
replaced with Dex II - scared to start it again before checking in here at the forum....

Linkage maybe? Worn gear? I don't know transmissions well and could really use some help on this one.


Thanks in advance for your advice!