hi guys. new to boating. just bought my first one, an 81 glastron 16' open bow with a suzuki dt115. the motor runs good, it shifts into forward gear nicely. pops in pretty easy and works well up to full throttle. the problem i am having is with reverse. as i begin to bring the control back from neutral it starts to grind pretty good and then if i am brave enough to keep going the motor will begin to bounce off the trim cylinders as it pops in and out of gear. its pretty loud (and embarassing) with the gears grinding and the motor bouncing. i have changed the gear oil, old oil was black but not milky and no signs of metal shavings. the control cables are looking pretty bad, cracked housing and have a relatively sharp bend at one point near the motor. so thats one area i know i need to look at and plan on replacing. beyond that it would have to be something in the gear housing. not sure where to look though. seems like a clutch issue most likely. i'm a good mechanic with cars but totally new to boats so i could use some help. thanks.