75W140 or 85w140, anyone running it?
 

Anyone running these heavier oils in their drives? I know that Ford, and some other manufacturers, have specified 75w140 when towing heavy, in the rear diffs. I would think, that your typical sterndrive that is pushed pretty hard, whether it be due to HP, boat weight, prop style, etc, is a pretty severe load. I know the bravo drives that dont hold alot of fluid, can get pretty friggin hot. People think 75w90 is some super duper thick fluid, but when its at 200+ degrees its pretty watery thin.

I've been running your typical 80w90 in my SSM IV drives for the past few years since I've owned them. One drive was getting a little fuzz on the magnet at oil change. Thinking about going to the thicker oil. I can care less if it costs me a speed loss, IF it protects the gears from the severe loading/unloading (throttling) in a heavy boat with 800HP per side.

I use to run Synergyn 80w-140 Syngear II back early 2000's. Things I notice about using was - of course harder to pump in the outdrive and took a long time to drain when changes. Next the outdrive was quieter under load compared to Merc Hi perf gear oil. It also came out very clean and no material on the magnets.

A friend of mine who does oil analysis use to do all my oil analysis and the reports came out very well. I never had gear oil tested in anything over 575 hp. I will say this Mercruiser Gear oil High perf new and used samples were not impressive according to my friend. The first question he asked was, how much is the cost of their gear oil. After I gave him my cost (dealer) he laughed and said for the money they charge, you could do a lot better. I have not kept up with oil analysis service in years.

I run 75w110 Amsoil

I see the newer Ford trucks call for 75w140 in their diffs. My 2008 Grand Cherokee, calls for 75w140. My 1997 Chevy dually calls for 75w140. My Lincoln Town Car calls for 80w90, BUT, if it were a limo, with the same diff, they call for 75w140.

I cannot see any of those gears, being under as much stress as my boat drives, being held at full throttle for long periods with 800HP per side, in rough water.

You might be on to something. My '08 F150 calls for 75w140 synthetic gear lube in the rear axle. Do different oils affect operation of the cone clutch in the drive? Could there be any other drawback? (besides a little speed loss)

I don't have any clutches in my drives, but that seems like a good question.

I was shocked to see 75w140 specd on my jeep cherokee. Esp with how hard the car manufactures try to meet mpg concerns.

I know people hear "90" or "140" and they think it's sludge. But a 90 weight gear oil, isn't like a 90 weight engine oil. I'd think if my Jeeps diffs been working just fine with 75w140, in the extremely cold winters we get around here, for the past 150k miles , it should be ok in my drives that never see operation in subzero temps. ? Just thinking out loud here

With the bravo drives obvious heat problem (low fluid capacity, white chalky buildup, need for drive showers), is the 75w90 getting too thin at high temps?

We often debate the brand of oil used to our ears bleed. But nobody ever discusses the weight of the oil?

Great post mt
this could use some testing, do you gain heat with a thicker oil or after warm does it all even out plus the added protection

'YOUR OIL IS FLOWING TOO FAST!!!'

Good idea on slowing it down with thicker oil ..... = more cooling

FWIW, too thick or viscous of an oil actually retains thermal energy more so than a lighter, less viscous fluid. People forget oil is responsible for about 40% of cooling inside a typical engine for example(I realize we are speaking on gear lubes, however they act as a coolant as well). Granted some applications spec and demand more viscous fluids, however running thicker than called for has the thermal penalty. To add to this guys think adding capacity is also a good idea in every situation. Guess what, it's not! Larger than needed capacity merely takes longer to heat up, and once it reaches said upper temperature it takes a lot longer to cool back down due to decreased turnover. A situation where more isn't always better.

I hate to bring it up again, but NEO 75w-90 has proven itself time and time again. It's not only about viscosity here. That's only one piece of the puzzle. If a gear oil isn't shear resistant and doesn't offer a robust extreme pressure additive, it's not ending life anywhere near a 90wt oil while at 100 degrees Celsius! People forget about shearing which is always a present force in any gear box.

Many manufactures are specing drivetrain fluids with CAFE in mind. Fuel economy over the absolute best protection. There are always compromises. However, it's telling that some manufactures are calling for 140wt gear oils. My feeling is maybe it has something to do with their expectation of shear/load/maintenance of said gearbox... Building in a safety feature by merely selecting a thicker fluid makes a lot of sense( for example the used 140wt gear lube has a 90-100 wt at the end of life vs a 90wt which would/could shear down much more). However if you were to buy the best (OEMS are all about profit, so obviously they never do this), shear and lack of maintenance would be things rarely encountered.

And remember 90wt gear oil is measured at 100degrees celcius. The only way it "thins out" is if it shears down in grade. It's physical appearance and behavior(thinning with heat, thickening during cool down) with temperature mean about as much as the color of used motor oil, nothing! The only way you will know if it's doing its job and not shearing to an unacceptable level is to perform a used oil analysis. Film strength is a pretty strong barrier when it's in place. This is what separates searing hot metal, in a tiny space.

Heres a good read on gear oils. Looks like out of the group of gear oils, Amsoil Severe Gear took first place.

http://www.lastgreatroadtrip.com/wp-...comparison.pdf

Good read with some interesting results
Apparently if you spend enough on advertising you can charge what you want
Borgie what's neo oil?

Seems like in the automotive world, when severe service is anticipated , like towing , hot summer temps, heavier loads, the manufacturers are spec'ing 75w140. Considering they have to warranty these things, I can't see where the thicker oil would cause any damage. It must help if they recommend it.
I've been running the 85w140 in my semi truck rear ends with no issues ...

We all pretty much run mercury drives. And they spec 75w90. However , they also say no synthetic engine oil, have leaky headers, valve train issues, and without a doubt, durablity issues with the bravo drive. So I'm not quite so sure I will take that 75w90 only recommendation to the bank. A 300hp engine with a 3 blade prop on a 19ft bow rider , isn't gonna make the same heat, or sustain the same loads as a 525efi 42ft boat setup. Idk. Maybe I'm way off on this

Anyone every put a temp sender in a bravo drive in a High Performance application? I wonder how hot they actually get fluid temp wise?

I use 75-140 synthetic from John Deere. It's about $24 a quart. We get it in buckets for the farm. I have no prob yet but i dont have lots of power like u guys.

My point is that OEM's anticipate shearing in gear oils, so s 75w-140 is used so that with use, it's still within acceptable viscosity range... Shear is a huge consideration and many gear oils do poorly in this dept. NEO is very shear resistant, hence the 75w-90 works very well as it stays in grade. They are using this stuff in the big boy boats with 1,200 hp so it's not your grandpas 75w-90. As for Mercury.... They don't blend oil let alone know a damn thing about them, much less how to build a true marine Performace engine. The bravo design is a total joke and the gear oil they recommend I wouldn't put in a 9.9 outboard let alone a bravo being beat on the regular by an angry BBC.

I will say it again, thicker isn't always better.. Take motor oil, you can have a 15w-50 and it is ok for the first 10 hrs of operation. After 10 hrs said brand shears to a 30wt... Then a little longer, 20wt... There are other "shear resistant" oils that will stay in grade, when this one will not. So just because it's a 75w-140 doesn't mean anything.

Great study, however that was done in 2007 and Amsoil has made changes since. Not saying for the worse, however the Severe Gear is different from that testing period. If some Amsoil sales guy wants the proof of this I have the email to prove it. Know you guys love to argue..

Many other brands in this test have been tweaked as well. Redline is one. Any oil company worth a darn is constantly evaluating their oils and making changes. For the consumer that's usually a win win.

Actually Mercruiser High performance gear oil is 80w-90 before that they had Mercury Premium Gear oil. It was the color of maple syrup. Sticky as glue also and was a climbing gear lube.

Also I have the outdrive temp senders / Gauge and all the wire in a complete kit to monitor your outdrive temps. . I am testing the whole set up as we speak and will should have it available very soon to sell..

Really not trying to turn it into a brand debate. I understand what you are saying about shearing and viscosity, etc.

What I am trying to determine, is what, if any, drawbacks would there be to running a thicker oil?

I suppose knowing the operating temp is one consideration. I mean if the drive oil never sees over 200ish, than it may be a waste. But if the drive oil temps are seeing 300 degrees, maybe it might be a consideration? We may know a 90 weight oil is capable of providing the proper viscosity at 210*, but what about at 250, or 300 degrees? Example

Say typical 25ft Baja outlaw with 496 Mag engine, bravo drive, 3 blade mirage prop. His maximum drive oil temp might be 190*. Then you have a guy with a 42 Fountain, with a pair of 525's, running 6 blade hering props. His maximum drive temp might be 290*. It would almost be like a having a F350 dually that never pulls a trailer, and operates in Minnesota all year, compared to the guy who has a F350 dually, that tows a heavy trailer, thru the arizona desert all summer long. Same gears, same housings, but extremely different operating loads and temperatures. My guess is with Ford, Chrysler, Toyota, GM specing 140w gear lube, is that they must believe the 140 isnt gonna cause the damage to the Minnesota truck, even though 90 would work better, where as the 90 might cause damage, in the arizona truck?

I see Neo also makes a 75w140, as well as their 75w90. I'd imagine they make a 75w140 for certain applications. Question is, what is that application? I'd guess that the lube engineer would need to know the operating temp and loads and what not, to specify which oil should be used?

With engine oil I can see where a thicker oil, can cause issues. I wouldnt run straight 50 weight engine oil in a new Z06 Corvette, or something like that with tight clearances, that was designed around using a thin oil. But this is more of your basic standard helical gear lubrication question. Its not like the oil has to flow thru .002 clearances when its 4* and snowing out.

Approved Lubricants - General: Gear lubricants acceptable under military specification (MILSPEC) MIL-L-2105D (Lubricating Oils, Gear, Multipurpose) are approved for use in Eaton Drive Axles. The MIL-L-2105D specification defines performance and viscosity require- ments for multigrade oils. ItIt supersedes both MIL-L-2105B, MIL-L-2105C and cold weather specification MIL-L-10324A. This specification applies to both petroleum-based and synthetic- based gear lubricants if they appear on the most current "Qualified Products List " (QPL-2105) for MIL-L-2105D. NOTE: The use of separate oil additives and/or friction modifiers are not approved for use in Eaton Drive Axles. Approved Lubricants - Synthetic based: Synthetic-based gear lubricants exhibit superior thermal and oxidation stability, and generally degrade at a lower rate
when compared to petroleum- based lubricants. The performance characteristics of these lubricants include extended change intervals, improved fuel economy, better extreme temperature operation, reduced wear and cleaner component appearance. The family of Eaton RoadrangerTM gear lubricants represents a premium quality synthetic lube which fully meets or exceeds the requirements of MIL-L-2105D. These products, available in both 75W-90 and 80W-140, have demonstrated superior performance in com- parison to others qualified under the MILSPEC, as demonstrated by extensive laboratory and field testing. Lube Sampling and Condition Monitoring: For information, contact your local Eaton represen- tation at phone numbers listed on the back cover of this manual. Makeup Lube: Maximum amount of non-synthetic makeup lube is 100%.
Viscosity/Ambient Temperature Recommendations: The following chart lists the various SAE Grades covered by MIL-2105D and the associated ambient temperature range for each. Those SAE Grades shown with an asterisk (*) are available in the Roadranger family of synthetic gear lubricants. The lowest ambient temperatures covered by this chart are -40oF and -40oC. Lubrication recommenda- tions for those applications which consistently operate below this temperature range, must be obtained through the Eaton Corporation, Axle & Brake Division

Grade Ambient Temperature Range 75W -40oF to -15oF (-40oC to -26oC)
75W-80 -40oF to 80oF (-40 oC to 21oC)
75 W-90* -40oF to 100oF (-40oC to 38oC)
75 W-140 -40oF and above (-40oC and above)
80W-90 -15oF to 100oF (-26oC to 38oC)
80W-140* -15oF and above (-26oC and above)
85 W-140 10oF and above (-12oC and above)

This is from Eaton. As they show here, as the temperature changes, so does the lube specification. Same rear end, just different temps

I would like to hear more about the Neo oil

Does the sensor go in the upper plug hole? I think that's the only place you would get a meaningful reading.

I worked as a heavy repair auto/light truck mechanic for 20 years. That means engine, transmission, transfer case and drive axle. Rear (and front) drive axles are one of the most durable parts on a car or truck. I saw very few broken drives, even on snow plow rigs. All hold up well and the Ford 9" is indestructible. Lots of older cars are still running with the original oil! It's hard to break a ring or pinion gear even with abuse. I wonder why the change in oil specs now. Especially if it may increase drag. :confused:

Very true. In the heavy haul trucking business myself. The rear ends are very durable , and most failures are simply from driver abuse. It's very common to see the rear ends go a million miles with normal service intervals and your basic gear lube. None of these big major fleets are running amsoil, neo, redline, etc. Cars I can't see having as much stress on the rear end. Your typical car production V8 might put out 300 ft lbs of torque, and only stays there for a short time. Otherwise it's consuming minimal power to maintain a steady cruise at 65mph. Now a tow rig hauling a 12k lb boat up a long grade with today's high output diesels, I can see then getting pretty hot and pretty loaded.

However, semi trucks also have large gears, and large bearings. Unlike the bravo drive, which has small gears and small bearings. They probably need all the help they can get. Whether it be a better quality lube, different weight lube, or both, idk.

There are other oils that are just as good as NEO, so not trying to turn this into a brand debate at all. But considering NEO happens to be a marine blended gear oil, is a 75w-90 And is highly shear stable, I think it's a very good example to use here.

Measuring drive temps sounds very intriguing, however it doesn't answer anything beyond maybe give a chemist parameters of operation for said oil being used(if you were to call said oil company for a gear oil recommendation). Like anything, the bravo drive for example was spec'd with a certain viscosity oil, in this case it's a 90wt. Beyond doing oil analysis, which is limited in what it tells you from a wear perspective without teardown, we only really know one thing, what the gear oil is doing chemically and physically(remember SHEAR), UOA's are not a good gauge of wear..

Unfortunately you would need to approach this in a unscientific way by running 75w-90 and 75w-140 in a shear stable formulation, same brand, same intervals, similar usage and perform multiple UOA's, magnet inspections along with complete tear downs involving measurement of gear wear surfaces to determine which is truly superior. However if wear metals are lower in analysis of one grade over another and magnets are clean you can roll the dice and hope it's doing what you think it is.

im going to say two things but im not getting into a pizzin match so dont get all bent out of shape.first,no gear oil in the world is going to make a bravo style drive stand up to big hp engines espically in heavier boats,the physical size of the gears just wont last long in these harsh conditions,second saying mercury knows nothing about making a high performance marine engine is a bold statement that is incorrect imo.the no longer produced 1075 is a good high performance engine and the 1350&1650 are epic.

I agree completely with your first statement and will agree to disagree on the second. Even with the best lube, there are only marginal gains in longevity. But if that's 50-100 hrs more, I will take it. No more pissing matches. I think you and I got off to a bad start. You know how opinions work... Doesn't mean we need to butt heads.

Oil is to keep things in 'contact' from wearing.

As far as I know it does not keep teeth from breaking off nor shafts from twisting. LOL.

That's not completely true. Some gear oils are specifically designed for "shock loading" which absolutely breaks shafts/gears etc...we all know the issues with bravo drive design. It's a ticking time bomb with higher horsepower. But shock loading is an absolutely proven issue and is encountered in the marine environment on a constant basis.

All gear oils are not created equal, and if anyone had shown that, Ams oil probably did the best job with their report back in 2007 from a scientific and factual standpoint.

100% correct but some people think the gear oil is the problem when infact the drive itself is the problem.

I think theres alot of drives out there that begin wearing the gear sets out, until they get thru the hardness of the surface, fatigue, and break.

While I do agree there's magical oil out there to stop drive failures, I still think a quality oil must be used. Otherwise, why don't we all just go to Autozone and buy the generic $3.99 a quart lube and go boating.

Bogey is somewhat correct. You can add some cushion with the oil, but you cannot take away forces.

I've broken many drives, and all where the result of torque loading...usually during planing.

I have had problems with my right hand (in cars, my right foot) doing what my brain tells it to do. LOL.

i agree that a good high quality lubricant is a must but my comment was more to point out the weakness of the bravo style drive.i have through the years been guilty of asking to much of the bravo style drive but i knew from the start that it was on borrowed time.i know that coolerman runs the neo in the 6 drives in his black thunder and it has big power,when he sais it is a good lubricant i am inclined to agree!

Yes force is force something has to give at some point.

Yeah I don't think its "magical" per se, more along the lines of better suited for said application. I absolutely agree that you need to run the best oil possible in a bravo. NEO is just one shining example of a product that's been validated in the field. There are others out there as you know. The stuff is pricey, but it beats the he** out of breaking a drive prematurely! Sometimes though metallurgy doesn't care about lube though, and stuff breaks. It's the gamble we all take.

I ran RED LINE in a drive I blew up.. it sat at the drives guys shop for a while and he said he`s never seen an oil stick to gears like that.. the stuff just didnt want to come off, hard to clean even.
I don`t know what that means but that was their ShockProof Gear oil.


You can still see it on the gear


http://33outlaw.zenfolio.com/img/s11...81169723-4.jpg

i used the redline shockproof lube in the v drive of my pro mod drag hydro,it ended the problems i was having,when the other guys asked me what lube i was useing i said MOBIL1 SYNTHETIC OF COURSE.

I like you more every time I read another post, I sure wished I worked with more people like you

Does anyone with twins want to run two different oils in each drive and let us all know which is better? LOL