Y not Synthetic GL-5 in gearboxes?

[xzostd1]

Why can't GL-5 synthetic lube be used in a Meritor 10 speed?
The Meritor specs show that straight weight engine oils can be used.
What about a 20w50 Mobil 1??
Bill
Menominee MI.

[Rawlco]

It depends on weather it is under warranty or not. If it is then you need to use a product that is approved by the manufacturer. If it is not then choose a similar product. For example Amsoil makes a synthetic transmission lube that will meet the Eaton specs, but needs a more frequent change interval than the Eaton branded oil. :? It meets all the independent tests but Eaton won't accept it under warranty. Each major lubricant manufacturer will have their own oil that will fit that transmission, so choose on price, availability, and the distributors ability to stand behind the product.

[JoeyB]

The back end (the hi/lo range selector) of the transmission is synchronized. Synthetic oil might be a little too slick for the synchro to work.

That's the same reason you don't use axle oil (the stuff with that smelly sulfur-phosphurs additive) in the box. They always called for straight mineral oil. The sulfer fouls the synchro- next thing you know it's grinding on range selection.

[roadranger]

I use Mobil One 15W50 in engine/transmission/wet clutch motorcycle applications and it is fine. The lighter grades of Mobil One have "friction modifiers" in them that cause the clutches to slip .

[JoeyB]

I think it would be an error to infer that if it's OK for the bike, It must be OK for the Merritor 10 speed also.

[roadranger]

Actually, as far as I'm concerned the faster a Meritor lunches itself the better so you can get a proper Eaton put in . Seriously, using an approved synthetic is the way to go for longest life - but I suspect the Mobil One 15W-50 would do just as well (but why chance it?). Same for the differential. The engines seem to do fine with mineral oils changed at the proper intervals. I do run synthetic engine oils in all my other motors but plan to just go with the new 2007 diesel oils coming out now for the road tractor - maybe adding a bypass filter too and doing sample testing to possibly extend the drain intervals?

[xzostd1]

I just bought my (Meritor Approved) $116.00 pail of Mobil SHC 50 synthetic gear lube.

Following Meritor service intervals of 500,000 miles it will last until I have 2 million miles on my Volvo :shock:
Bill
Menominee, MI

[Birken Vogt]

Multi-vis oils such as 15W 40 are not recommended for transmissions either because the gears chew up the viscosity additives and it becomes a straight 15W real quick. I have been using Delo 400 straight 50 engine oil and I like the feel it gives over straight mineral gear oils.

Birken

[Blind Driver]

Sythentic oils are not recommended for any application that has some of the softer metals in it.

[JoeyB]

Sythentic oils are not recommended for any application that has some of the softer metals in it.

That's interesting. Do you know why?

[Blind Driver]

The softer metal will eventually disolve :shock:

[Birken Vogt]

I think you meant GL-5 oils, synthetic oils do not react with metals any more than any oil

Birken

[xzostd1]

I did a un-scientific test
I put my containers of Valvoline 5w40 full synthetic....Rotella 15w40 .....and Mobil 50 synthetic gear oil outside in -14F temps.
The two synthetics are still shakeable
The non-syn. Rotella is not
Bill Tonight I'll test my Webasto engine heater after a -15 to 20F night

[bob h]

I did a un-scientific test
I put my containers of Valvoline 5w40 full synthetic....Rotella 15w40 .....and Mobil 50 synthetic gear oil outside in -14F temps.
The two synthetics are still shakeable
The non-syn. Rotella is not
Bill Tonight I'll test my Webasto engine heater after a -15 to 20F night

if you check your engine owner's manual, you might discover that your engine should be running a API C-rated 10w30 when ambient temps remain below 20 degrees... you oughta see 80w90 @ -30 ;0)

p.s. - what conclusions have you drawn from this test?...

were you surprised?

will the results effect your choice of engine oil?

[Blind Driver]

I think you meant GL-5 oils, synthetic oils do not react with metals any more than any oil

Birken

Wrong. Check out the manufacters websites.

Also, which is not widely known, in older engines do not use engine oils wih the starbrurst logo. They are missing an additive which was found to clog cat converters(in autos).

E.O.S. assembly lube is a good substitute. Available at your GM dealer.

[bob h]

quote="Blind Driver"]

I think you meant GL-5 oils, synthetic oils do not react with metals any more than any oil

Birken

Wrong. Check out the manufacters websites.

provide a link!!!

Also, which is not widely known, in older engines do not use engine oils wih the starbrurst logo. They are missing an additive which was found to clog cat converters(in autos).[/quote

huh?

[Birken Vogt]

I think you meant GL-5 oils, synthetic oils do not react with metals any more than any oil

Birken

Wrong. Check out the manufacters websites.

I don't have time to "check the manufacturers' websites", could you please provide a link? What was this in reference to again?

Birken

[Blind Driver]

Additives have been taken out of automotive oils over the last 10 years because they foul the cat converters.

Many of the classic car guys are now just finding out about this.

Don't think the diesel oils have been affected...yet

[bob h]

Additives have been taken out of automotive oils over the last 10 years because they foul the cat converters.

Many of the classic car guys are now just finding out about this.

Don't think the diesel oils have been affected...yet

hmmmm, i disagree =(

i'm pretty sure that engine oil additive packages have only ever increased

each additive has a job, if it's not there that job is not done.... friction modifiers, for example, reduce friction improving component wear and resistance to rotation (energy conserving oils). egr engines require increased crankcase acid control, increased ash raises the oils base #.

the problem with old... old engines that have only ever used older rating (API-SB, SC) oils is that they had few dispersants in the additive package, allowing a slow build-up of deposits

current oils have lots of dispersants, nearly eliminating deposits altogether

the problem is that these additives break away deposits in the old engines and clog oil galleys and pumps

[xzostd1]

They have decreased the zinc in automotive oils to avoid fouling cat converters. The problem is that older flat lifters need the zinc to avoid camshaft lobe wear. Most late model vehicles have roller lifters which don't need the zinc content. I have some info on actual zinc content of auto + diesel oils that I can probably dig up if anyone is interested.
It becomes of great concern in racing with higher cam lifts and spring pressures.
Bill