Hi,Does anyone have any idea what grade gear oil I should put into the lower unit. I have the manual but it doesn't recommend the grade. Is there a generic grade and brand that is common to all small outboards? Any help at all would be great.
Usa a High-Viscocity gear lube made for outboard motor lower units. Yes, they seem to have a generic grade.That is, most do not list a grade on the label, mine says 80w-90.Lower unit gear oil is formulated for underwater applications.
I use and have always recomended a synthetic lower unit oil. It protects better all around, You can use any synthetic 75-90 synthetic gear lube as they will all meet the requirements of outboard use. The main difference in outdrive and automotive gear lubes is the antifoaming agents. Synthetics will all have this quality. Also they will protect better if by some chance you were to get a little moisture where it doesnt belong! Amsoil is the lube of choice but others will work!
Originally posted by LubeDude:I use and have always recomended a synthetic lower unit oil. It protects better all around, You can use any synthetic 75-90 synthetic gear lube as they will all meet the requirements of outboard use. The main difference in outdrive and automotive gear lubes is the antifoaming agents. Synthetics will all have this quality. Also they will protect better if by some chance you were to get a little moisture where it doesnt belong! Amsoil is the lube of choice but others will work!
Thanks a million for your reply. Unfortunately Amsoil is not available here in Ireland but there are plently of good brands around that I am sure will be just as reliable and safe.Again thank you
Quote:
Originally posted by LubeDude:I use and have always recomended a synthetic lower unit oil. It protects better all around, You can use any synthetic 75-90 synthetic gear lube as they will all meet the requirements of outboard use. The main difference in outdrive and automotive gear lubes is the antifoaming agents. Synthetics will all have this quality. Also they will protect better if by some chance you were to get a little moisture where it doesnt belong! Amsoil is the lube of choice but others will work!
I've read a lot of different opinions on using full synthetic as gear lube as the synthetic does not have the same "cling" properties as dino-lube does. It is suggested that an inadequate amount of lube stays stuck to the gears that are not fully emersed in lube to complete a full revolution. I know this is an issue in auto differentials, does anyone have any opinion on this theory in lower units?
LubeDude, I think your refering to the property of syn to adhere to metal but I'm refering the ability to have a sufficient quantity to cling to meshing teeth of gears in motion to inhibit wear, not the lubrication of smooth surfaces like cyl walls and bushings where syn lube obviously accels. There is a web site where a guy has a transparent gear "machine" and he tests several types of gear lubes and additives. The pet lubes are superior at protecting gears within his test parameters. I'll try to find the hyperlink. It is very interesting. Also one of the American truck manufacturers, it may be Dodge, specifically advises against using syn lube in differentials due to the design of the splash deflectors not being able to supply enough lube to the gears due to syn lube's more "liquid" state, if you will.
Most of the test you are refering to are selling some kind of snake oil and try to tell you anything they can to sell there product, I firmly stand behind synthetic gear lubes to out perform any conventional gearlube. Anytime, anywhere, any temperature, any aplication, Period!!As to using synthetics in the Dodge differentials, They actually came out shortly after putting the Cummins diesels in there P/Us reccomending synthetic gear lubes due to differentials failing due to the extreme touqe of the engine! I beleive now that nearly all the heavy duty trucks out there, Ford, Chevy, and Dodge come with synthetics from the factory!
I guess there's no arguing with a guy who goes by the name LubeDude. And no, by the way, the web site I was refering to is just an independent guy who is doing this out of his shop. No sales. And as a matter of fact most of the lube used by the auto makers like the new dodge tranny fluid are synthetic blends which are not really sythetic at all, as I'm sure you know since you're the LubeDude! I'd find the web article on synthetics in diff's that was put out by the manufacturer, but I'm pretty sure you'd find some way to scientifically refute the data like "that's all B.S." but hey, looking back at my first post, I guess I did ask for opinions, so thanks for yours.
Hey, Lose the attitude!! Im very willing to see what ever you want to show me and will look at it with an open mind. To think I am just shooting from the hip and do not have facts to back me up is somewhat insulting, Show me the facts and I will reply to them with facts! I know better than to just take someones word for something that I beleive to be BS!Copy and pasteProper differential and transmission lubrication requires a product which will satisfy a wide range of service conditions. The off-set gear intersection design in hypoid differentials requires a high degree of extreme pressure chemistry to prevent scoring of the ring and pinion set under high-speed conditions and spalling under low-speed / high-torque conditions. High temperatures can cause a breakdown of the petroleum, forming insoluble sludge which can plug the bearing cages and cause oil starvation to the bearing surfaces. Limited-slip clutches require additional slipperiness compared to conventional hypoid differentials in order to prevent the noise and vibration producing stick/slip phenomenon. Most of these friction modifier supplements detract from the load-carrying capability of the lubricant. Synthetic 75W90 and 80W140 Gear Oils have been developed to be used in both conventional and limited-slip differentials, providing additional slipperiness for the limited-slip units and also enhance the load-carrying capacity of the gear oils. The synthetic components used provide a naturally high viscosity index, which means that Synthetic Gear Oils have a relatively constant viscosity with changing temperature. They will not thin out as readily at high temperatures when compared to petroleums and they are much more fluid at low temperatures. Figure 1 compares the high temperature oil film thickness of Synthetic Gear Oils compared to petroleum products. Synthetic 75W90 provides a much greater viscosity than a petroleum 80W90 (SAE 90). The contact zone temperature can be several hundred degrees greater than the bulk oil temperature. This difference in high-temperature viscosity and the ability to more effectively lubricate in extreme temperatures may prevent oil film rupture at high temperatures and loads. IMPROVED LOW TEMPERATURE FLUIDITYCold weather can be just as damaging to differentials and transmissions as sustained high-temperature use. Rapid oil flow to the bearings and adequate lubricant splashed to the gear teeth is critical to prevent component fatigue and premature failure. At -15°F an SAE 90 gear oil will take more than 5 minutes to flow to the bearings while Synthetic 75W90 requires only a second. This dry lubrication can cause rapid fatigue damage. High viscosities when cold will also rob the vehicle of considerable power until the lubricant has fully warmed up.
That was not attitude, that was just a statement, In my opinion that is what I would call it! BS, Myth. rumor! It was not a personal attack, I do not do business like that, although I have been known to not have much tact!! Sorry if Im too sure of myself!
Mariner 3.5; Lower unit oil
Im very willing to see what ever you want to show me and will look at it with an open mind. To think I am just shooting from the hip and do not have facts to back me up is somewhat insulting, Show me the facts and I will reply to them with facts! I know better than to just take someones word for something that I beleive to be BS!
Sorry if Im too sure of myself!
I'm new to this forum and learning alot of new tricks. I'm not trying to make waves(no pun intended!)
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