I have a 1986 340 Express Cruiser. Port transmission overheated and blew dipstick and sensor plug resulting in a small flash fire. Only charred some wires. Velvet model #10-18-004 1.52 was rebuilt and a damaged ring gear was replaced. When it was started (after rebuild) it still had a significant "cluncking" sound in reverse. This was corrected when throttling up and finally by increasing the idle speed by a few hundred rpms. Still had a slight rotation when in forward (it has done since I've owned the boat..3yrs). Test run seemed to go very well. Next day I was pulling out of dock and noticed port didn't seem to engage in forward, then seemed ok for a short time but then was definitely slipping around 2000-3000 rpm. Returned to dock to take a look....still pretty quiet in idle reverse, noted that there was no rotation when in neutral (for the first time ever). Without changing throttle the rotation speed in reverse was probably 2-3x the rotation speed in forward. Fluids were well monitored during the test the previous day (but didn't check day 2). No apparent leaks. Does anyone have any ideas what could be happening if this is not a fluid problem? Thanks for any help!