The Most Negelected Piece of Gear!,

[seapower]

From what I see daily is your transmission. Once again I just got off of a very nice boat that has been running 2 &1/2 quart's low on oil. That may not sound like much, but given the capacity of the sump, it's alot. Your transmission oil level need's to be checked as often as your engine oil is checked, period!!! When a transmission cooler start's leaking, the fluid can empty very quickly, costing you a very expensive repair. There are only 2 places a transmission can loose coolant shaft seal's (in put and out put shaft seal's), this oil will be seen in the bilge and the cooler. The oil that leak's out of the cooler can be detected at the over board discharge of the raw water (in most cases the exhaust). The oil should be changed at least yearly. I know the oil "look's" clean, but it is subjected to the heat of compression. The reason it stay's clear as apposed to your engine oil is because it isn't subjected to carbon from fuel burn. Your transmission is nothing more than a "closed" hydraulic system. The transmission cooler should alway's be clean, with an un-obstructed flow of raw water, that is the life of you gear, clean cooled oil. The oil serve's your bearing's, clutch seal's and clutch packs' themselve's. One thing you can do to get a good idea about the "health" of your gear is to use a telescoping magnet and run it down into your transmission sump. It should come out clean. If there is metal (bearing material and clutch material) you have a problem. By simply paying attention to your oil and keeping up with the zinc's in the cooler, you should get many year's out of your gear. From my experience a well taken care of transmission they can last the life of 2 engine's. Don't forget that little gear box, bolted to the rear of your engine. One other thing is your shaft alignment. Vibration is the enemy of your bearing's. Frank

[clt_capt]

Great Tip Frank.

[Double D]

Good stuff Frank. I know I'm guilty

[seapower]

I mentioned running a telescopic magnet down into the sump, that is only if you have a clear shot down there (some do not). If you try to force a magnet down and have to pull it back up, it could get caught and pull the telescopic shaft in two. So only if there is a clear shot down. And I have also found that the gear's that use ATF (with the exception of the old Velvet Drive's) are not nearly as robust as those using say 30 to 40 weight oil. So knowing that those are more "tender", keep a better eye on them. Some will have filter's, change those as part of your maintainence. Frank

[Avenger]

Excellent point Frank. Shear forces and temperature are hard on oil whether in an engine or a transmission. The only thing I might add is doing periodic oil analysis. It may not be justifiable for smaller boats, but if you've got big dollar gearboxes it could be a significant potential cost-saver.