1999 Catalina MK II.. While motoring out yesterday after about 10 minutes at 2800 rpm, the transmission made a wired sound, like it was grinding the gears. I immediately lowered the rpm and the noise went away. I tried again and after a minute the sound came back. I limped back to the slip at lower rpm. I reviewed the transmission fluid level and discovered that the transmission was overfilled with fluid. I changed the transmission fluid. The fluid that came out was a dark pink. What I am thinking is having a transmission expert come over, secure the boat to the dock and the run the boat in forward and reverse to test the transmission. I don't want to get caught in open water without a motor and have to call a tow. I am at the Rhode Island Yacht Club, not at a marina, in Cranston, RI, so I have to have someone come over to look at it. If anyone can comment and reference a good transmission mechanic in Rhode Island. Has this happened to anyone with an overfill of transmission fluid or the like? Thanks
Bob & Maggie B. Hobby Time 1999 C36 MK II TM/Wing Hull #1796 Warwick, RI
A manual transmission only has a portion of the gears immersed in the oil pool and relies upon the gears to splash and carry lubrication to other internal parts. The fluted sides of the transmission supply a surface area where the splash is cooled before returning back to the pool. There's a delicate balance of friction, splash, and cooled oil flow back to the pool that is dependent on the proper amount and grade of oil.
Overfilling a manual transmission will cause the gears to "churn" in the oil more than necessary and create heat (because of drag) which can exceed the ability of the flutes to cool. Unfortunately Bob, the symptoms you describe indicate overheated oil and possible damage. You might try draining and refilling with oil and see if the problem returns by running up and down the river with you dingy handy as both additional drag and an alongside tow if necessary. Rhode Island Engine Company, founded in 1965 might be an option if a professional needs to be consulted.
Nick Caballero
Retired C36/375IA Mk II Technical Editor
Great advice, thank you. I have now changed the transmission fluid and wait further comments before proceeding. B
Bob & Maggie B. Hobby Time 1999 C36 MK II TM/Wing Hull #1796 Warwick, RI
It may be the transmission or something else. Might want to look at the prop. Could be fouled. Cracked strut or sometime with the cutlass bearing.
I've seen fouled props cause some wild vibrations.
I heard of zincs coming loose and makings trouble.
Loose bolts on bell housing.
Engine mounts OK?
More things to check?
Chuck Lennox
97 MKii Ventura Ca
Island Girl Hull #1611