being "to slippery" is a bad thing in a diff,then it flows to easily and the bearings starve for oil.Just because it is "better" on paper or a controlled experiment in a lab does not mean nothing in the real world.

Oh and Chrysler uses Timkin bearings and Spicer gears,some of the best in the world.

BOOM Roasted!

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2000 Cherokee Trail Hawk
3.5" R.E Superflex Lift, R.E Quick Disconnects, R.E Rear Driveshaft, SYE, OME Steering Stabilizer, ARB Diff Covers, JW Speaker Black Heated Headlights, Mickey Thompson 16x8 wheels, 245/75r16 Toyo Open Country AT's, 15 lb Powertank

2003 KJ Sport (BLACK) 230,000+Miles (Decommissioned)

And you don't think that Timken and Spicer aren't involved in sourcing from "low cost countries"??? Even Caterpillar sources castings from overseas. If it means doing large volume business or not based on the extreme cost pressures of automotive customers, they will source from wherever they can if it meets the specs and requirements.

I'm not saying that Timken and Spicer are junk. But I am sure they make various levels of quality based on what the customer is willing to pay. And, based upon the way the CRD eats u-joints, ball joints, EGR valves, FCV valves, CAC hoses, frozen brakes calipers, etc. I'm pretty sure that Chrysler spec'd cheap crap. I worked for a Tier 1 Chrysler supplier and I heard multiple times from various Chrysler engineers that they only had to get it out of warranty. That was the target life cycle of a part.

I really do like the CRD - enough so that I've not really made an effort to sell ours since we bought a different vehicle for the wife to drive. But it has had far too many major issues by 80K miles; if it was a '75 Pinto I'd accept it, but not 30 years of automotive evolution later.

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'02 Jetta TDI Wagon 5 spd (mine)
'10 Outback (her's)
'05 CRD Sport (hangar queen)

How do you think they tested the original dino stuff? ...in a controlled experiment in a lab, and then they compared the synthetic stuff to it. If testing is done under the same conditions--and there's a number of ASTM standards for it (and probably SAE ones too)--then lab testing and real world performance should translate and be relative. I suspect that the manufactures then backed this up with real world testing...my employer would.

I remember in that previous thread that it was stated that the guys at the rear-end shops were experts at building diffs and not tribologists. If they were to:

1.) Have the heat capacity and ability to transfer heat measured of the various oils to back up their "air-tight conclusions."
OR
2.) Do some real-world testing by strategically placing sensors that measure the surface temps of the ring&pinion, the spider (or other ancillary gears), the oil temp, the temp of the outer diff housing, and the ambient air temp while driving the exact same vehicle under exactly the same conditions, I'll by the argument.

Is there a possibility that the people who are using the synthetic lube are just simply beating the crap out of their vehicles? What is the sample size of their basis? Have there been like 5 synthetic lubricated diffs fry and then only 2 dino lubricated diffs croaked and therefore the synthetic lubes lead to 150% more failures or something like that? Are they basing this on the diffs they are rebuilding for the first time...the previous builder other than them may not have done something right in the first place.

I change my engine oil every 10,000 miles because I'm using synthetic. If I was using dino, it would probably be every 5-6000 miles. This decision isn't based on oil analysis. It's based on what the service manual recommends, that I drive primarily highway miles, and a wee bit of blind faith that it's okay to do this. ...see the corollary?

There not chemist,they build axles.There world world testing was after they built the axles the owners would use full synthetic and kept burning up pinion bearings.They started stating for warranty to be honored to use only 85w-140 dino gear oil and the problems disappeared when the owners started using dino gear oil,no changes to how they built the axles.That is the 1st thing they always ask when you call with a ? about your axle from them.

Of course those who purchase there diffs abuse them,from extreme rock crawlers to 2000hp drag cars.Real world testing in those venues proved dino was better in diffs then synthetic.There sample size is in the ten thousands(for Currie alone).


Now synthetic oil is not bad,for your engine it's great,and for your trans and t-case.Advance Adapters you makes my t-case(AtlasII) only approves of only a few oils for there t-cases which are Torco MTF,Amsoil MTF(75w-90),Castrol Syntec 5w-50,Valvoline 20w50,or Mobil 1 15w50.

I really find that interesting. I wonder if it's a viscosity issue?? i.e. 80W-90 synthetic was being used rather than 85W-140? And, as the Amsoil white-paper shows, not all lubes are created equal - synthetic or not.

I'm guessing there is more to the pinion bearing problem than simply heat transfer capabilities of the oil. Synthetic oil is fundamentally the same stuff as dino oil - hydrocarbon molecules. The difference is synthetic oil molecules are manufactured from a much simpler base molecule that is 'assembled' into a specific size and type rather than the random "cracking" of crude oil down to molecules that are 'close enough' to what is needed. I'm talking about Group IV/V PAO base stocks - REAL synthetic oils, not the Group III "synthetics" like Castrol Syntec.

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'02 Jetta TDI Wagon 5 spd (mine)
'10 Outback (her's)
'05 CRD Sport (hangar queen)

It's funny how just about every class 8 truck built has synthetic oil in the trans and diffs. They also specify longer change intervals with synthetic oils. Maybe you should call them with all your inside info. You could save them big $$ with warranty claims. They might reward you!!

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2005 sport crd-SOLD No regrets

Actually, non-synthetic gear oil lasts longer. Back in the day, we would go 100,000 miles which was the life of the vehicle without changing it at all. Never had a problem with the rear end.

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2006 Sport CRD

Could the Aztecs have known, that in 2012 after a 4 year experiment, our country would cease to exist?

General Information
Eaton Lubrication Philosophy
In promoting component reliability and longevity, proper lubrication is the key to a sound and effective maintenance
program. Without effective lubricants at proper levels, remaining maintenance procedures will not keep components
functional.
We believe synthetic lubricants have proven to be superior to petroleum products and represent opportunities to promote superior
maintenance and bottom line operating performance while significantly extending component service life and reliability.
Standard Fill Lubricants
Transmission and Drive Axle lubricants must meet a number of lubricant industry requirements. Refer to the enclosed charts to
select the proper lubricant.
Extended Drain Lubricants
Extended Drain Roadranger synthetic lubricants offer superior thermal and oxidative stability for extended product performance
and reliability.
The superior performance characteristics of these lubricants enable Eaton and Dana to offer extended drain and extended
warranties. Added benefits include a more efficient drivetrain that translates into proven fuel economy savings over mineral
based lubricants.
Important: Using Extended Drain Roadranger synthetic lubricants is required to maintain Eaton and Dana extended warranties.
It is important to use the lubricants that meet the current specifications set by Eaton and Dana. Look for the appropriate approval
code on the container.
Transmission - Eaton Specification: PS-164 R7
Drive Axle - Dana Specification: SHAES-256 Rev C
Drive Axle - Dana Specification: SHAES 429 (Vocational)
Use of lubricants meeting these specifications will ensure the highest performing lubricants for maximum performance.
To identify Genuine Roadranger Lubricants - look for the Genuine Lubricants Label on the container to ensure you have Genuine
Roadranger Lubricant

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2005 sport crd-SOLD No regrets

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2005 sport crd-SOLD No regrets

Bug difference when comparing a diff that holds 2qts to one that hold 15qts+.

Funny thing they do not recommend synthetic gear oil is your diff has the Detroit Locker installed.............



http://www.eaton.com/EatonCom/ProductsServices/PerformanceProducts/Products/Differentials/FAQ/index.htm

No difference. They operate the same way with the same parts. Torque is the only thing different. More torque=bigger parts. Tell me again how dino is superior to syn?? Because they reccomend it in Detroit lockers??? In order to keep your extended warranty on Meritor and Eaton equipped diffs and trannys you MUST run synthetic. That really says it all. Not to mention the oil change intervals are Double with the synthetic. You would think it would be the other way around with dino being superior...

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2005 sport crd-SOLD No regrets

And the big difference is WHAT? Spell it out for us. Where is your DATA that says the thermal conductivity, density, or specific heat of synthetic oils is different from conventional oils? We are tired of your urban legends!

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05CRD: GDE Hot ECU & TCM tunes, Provent, Cat filter, Facet lift pump, TransGo kit, Florida TC, Samcos, stainless brake lines, HDS thermostat, Renegade light bar,
RL super sliders, Bilstein adjustables, Al's Gen 4.5 Arms, 235/85-16 Duratracs, DTT rear, Elocker front, EVIC+TPMS, Turbo timer, McNally pillar gauges, Weeks Stage II kit.

I don't need any data,real world experiences is better then a piece of paper.

What data do you have to say that syn is better then dyno gear oils?

Funny thing is you go by CATCRD,I imagine you have something to do with Caterpillar,which by they way mostly only recommends dino oils besides for there engines.

That is one of the dumbest things you have posted yet.
#1: Lubricity and viscosity are not interrelated when comparing Dino to Synthetic. By your reasoning synthetic oil is the worst thing you can put into your engine because it is too "slippery".

#2: Controlled experiments in the lab are the ONLY way of comparing two different oils. It's called "science". It is how ALL advances in automotive engineering are made. Someone has a theory about why they think something occurs. The only way to prove or disprove the theory, is by controlled experimentation. Individuals, corporations, and manufacturers make assertions all the time that their service is the "best", or that their truck is the "longest lasting", or that "my car is the fastest". The only way to verify or disprove these claims is with controlled testing.

Btw, a double negative makes a positive.

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Manure green 2005 CRD sport4x4, GDE Hot tune, Cat Gut, OE skids, Draw tight hitch, Duramax lift pump, 160K on multiple varieties of fuel, XM radio, Escort live with Redline, fog light mod, GPS, Icom IC7000 all band radio call sign KC9QPF, Grabber AT2s on Soft 8s, FIA grill blanket.

Look, I really have no care of what anyone decides to put in their differentials. Go with your gut on that one.

I will take issue with the synthetics are not good for differentials comments. This is not based on fact. My differentials in my semi, by using synthetics, get the warranty bumped up from 500,000 miles to 750,000 miles. Why would they do that if synthetics are bad? And Eaton corp prefers using synthetics, but does allow conventional gear lubes. Not only is the differential in question here, but also the lubrication of the inter axle as well. There is quite a bit of high tech going on under those trucks, and some pretty high pressures and heat. Pulling gross weights of 80,000 lb up 6% or better grades for several miles on a hot day with engines kicking out 1600-2000 ft/lb of torque is pretty trying on drive train components. Yet in all this, the manufacturers PREFER that synthetics be used. Must be a reason.

It would seem that some here just have issues with synthetics in general. Could care less on that one. I do take issue with reverence for particular brand names, but one cannot make a sound case that synthetics are not a good idea.

But, go with what you choose. You will anyway. If what you do works, great.

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Environmentalist Green + Socialist Red = Facist Brown

2006 Liberty CRD, Frankenlift II, Al's A Arms, Moog LBJ's, GDE tune, Etechno GX3123 Glow plugs, Fumoto drain valve, Elephant hose CCV mod.

Wrong. Cat, Detroit, Cummins, International, Volvo, Mack, etc, in the last few years, have recommended synthetics. As does the Technology and Maintenance Council, which is the defacto trucking industry standards committee on maintenance issues in trucking.

What data? How about warranties extended 50% by drive train manufacturers if synthetic oil is used. They must have done the research to enable them to stick their neck out and extend a warranty from 500,000 to 750,000 miles on differentials and transmissions if synthetics are used.

I don't work for any of these manufacturers, I just have to pay out hundreds of thousands of dollars to them to buy their products. It costs me dearly to lose a diff or tranny in a semi. If Eaton recommends synthetics, and they give me 50% more warranty if I do so, that is solid enough for me.

Frankly, it amazes me that people who play with toy diesels seem to claim to have the inside skinny on what to use in these setups than those that their entire business' involve utilization of this and heavier equipment. Those business' have serious bucks on the line and don't have time to fiddle with silly "I know better than the manufacturer" arguments. The TMC has spent millions of dollars and countless hours researching these issues and has made some definitive statements regarding this. Their general consensus is that synthetics perform better than conventional lubricants and are recommended.

They have got more real world experience in this than all of us put together ever will.

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Environmentalist Green + Socialist Red = Facist Brown

2006 Liberty CRD, Frankenlift II, Al's A Arms, Moog LBJ's, GDE tune, Etechno GX3123 Glow plugs, Fumoto drain valve, Elephant hose CCV mod.

Just wanted to say thank you and I appreciate the help for the Liberty differential info.

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2005 Liberty CRD, 245/75R16, OME CRD Springs front, OME HD rear

Came across this in a web search http://machinedesign.com/article/save-e ... anges-1122


I went out in the garage and looked at the carrier bearings on my old diff that they took out of my rear axle when I had the DTT installed. After 48k miles on synthetic they are pristine. No wear marks or heat discoloration on rollers or races. Oil was changed once at 12k.

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05CRD: GDE Hot ECU & TCM tunes, Provent, Cat filter, Facet lift pump, TransGo kit, Florida TC, Samcos, stainless brake lines, HDS thermostat, Renegade light bar,
RL super sliders, Bilstein adjustables, Al's Gen 4.5 Arms, 235/85-16 Duratracs, DTT rear, Elocker front, EVIC+TPMS, Turbo timer, McNally pillar gauges, Weeks Stage II kit.