Gear Oil of choice?

[DiscoveryXD]

What diff gear oil do you guys run in your trucks?

I've been using Mobile 1 75-90, but I'm curious what everyone else uses since I've been having diff problems lately.

 

[rusty_tlc]

In my FJ40 I run the walmart brand 85-90. I change the oil every year on that truck and it sees maybe a couple of thousand miles a year, but they are hard miles. No real point in using good oil. My theory is that since it sees a lot of heat and dirt I'd rather do frequent oil changes with less expensive oil.

I'll be interested to see what everyone else uses since it's about time for fluid changes in the 100 and 60.

 

[WILLD420]

The walmart brands of oil are rebadged domestics. They change manufacturers frequently, but are normally similar to quaker state or castrol oils.

I usually run whatever I find on sale. The only time I use something special is in a rig that will be used for towing heavy or has an undersized axle. Running a synthetic is good insurance for one that is run hard with heavy loads.

As for hardcore rocks, I hear the pros are having good luck with some of the special 180-200 wt stuff since it absorbs some of the shock loading. I wouldn't run it on the street, but if you are having problems with galling gears or brinelling locker gears it could help.

I refuse to run penzoil motor oil, but they have some pretty good gear oils and trans fluids. In fact, I used Penzoil synthetic marine gear oil in my old flatbed since I knew it would be neglected and abused. I figure if it's good enough to run in a $4,000.00 outdrive under water, it should work in an old truck that tows a little every now and then. Besides, it was on clearance for $2.00/Quart at Walmart...

I have seen no difference in temps between a cheap semi-synthetic and a full synthetic when used in manual transmissions or diffs when loaded up to and over their design limits.

For people who use their rigs for water play, the marine gear oil will allow you to put a drain plug in the housing and drain the water out after playing. The oil usually will not absorb the water if you don't get it too hot. Drive it to get it good and warm, let it sit overnight, go out and let the water out the bottom, just like a boat does. Beats changing out 4/Quart oil every time you go swimming.

 

[locrwln1]

I'm with these guys, I buy whatever and have used them all. Haven't really noticed a difference in any of them. I just run whatever the manufacturer recommends. As long as it meets the specs, I wouldn't worry too much about the name.

I ran hi-dollar synthetic in my 4runner and realized the first time I had to drain it to do some repair work, that it just wasn't worth it. It didn't look any better or worse than any of the dino oil. If it calls for synthetic, then run it, if not, don't waste the money. You will most likely be draining it anyway. It is just the nature of what we do.

Jack

 

[chicago]

Me too. I buy the rated stuff and what is cheap. Im in and out of the axles too often to be that concerned with longevity of the fluid.

 

[rusty_tlc]

..... You will most likely be draining it anyway. It is just the nature of what we do.

Jack

Me too. I buy the rated stuff and what is cheap. Im in and out of the axles too often to be that concerned with longevity of the fluid.

True statements, either you are breaking something or changing something. Either way 12 months is a long run for a oil fill.

 

[spressomon]

When I used to hang out, too many years ago to admit, with a German master tool and die maker (this guy was brilliant in the fab and design world) we tested dino and syn oils. His method was pretty simple: Used each as cutting fluid on lathe and milling operations. The syn's, and this is back in the day, ability to significantly reduce surface friction made it not such a good cutting fluid.

Another little test another similar type of guy showed me back in the day: He would take a metal pan with a film of oil in it and heat the bottom with a flame. The hot spot on the pan would cause different oils to move away from the hot spot at different rates. The worst performers were from multi-viscosities. IOW a 10W40 would move away from the heat source sooner and more aggressively than a straight weight. But we never 'tested' syns just dynos. Like I said it was too many years ago to admit .

But for differentials especially I think, as some of you have stated, it makes more sense particularly in our relatively mild climate and our type of use, to use the cheap stuff and drain it out after every trip with axle deep water crossings. Its amazing how fast, even with properly vented diff housings, cold water gets sucked past seals by the hot diff!!!

Any cheap but clean oil/lube beats dirty and/or contaminated expensive syn oil in our climate!

However I do use syn in my auto trans. I did notice slightly better shifts after I converted. But it could be all in my head And I use syn in the motor for its extended oil change intervals...and this last year with 20k+ miles on the Hundy it sure made life a little easier

 

[slvrbck]

I run Lucas in everything, I have always been a little sketchy about using cheap stuff. That comes from my Dad and his race cars though.

 

[rusty_tlc]

I run Lucas in everything, I have always been a little sketchy about using cheap stuff. That comes from my Dad and his race cars though.

The F series engine is more like a tractor than a race car engine

 

[DiscoveryXD]

Cool, thanks guys. I was wondering if the oil I was using had anything to do with the problems I've had....

I've seen some test (one was on spike tvs "muscle car") where they compare synthetics to non and it was a huge difference (atleast on the test.). They loaded bearings with different brands and the synthetics outlasted all the rest by a long shot

 

[slvrbck]

The F series engine is more like a tractor than a race car engine

That's why I don't have an F engine anymore.

 

[rusty_tlc]

That's why I don't have an F engine anymore.

Mo Skinny pedal Yea!

I kind of like chugging down the trail with my 2F, it's very relaxing.

Sometimes I even sneak in a nap while I'm driving, us old guys do that.

 

[WILLD420]

Cool, thanks guys. I was wondering if the oil I was using had anything to do with the problems I've had....

I've seen some test (one was on spike tvs "muscle car") where they compare synthetics to non and it was a huge difference (atleast on the test.). They loaded bearings with different brands and the synthetics outlasted all the rest by a long shot

I don't remember all the problems you've had, but I doubt very much they were lube related.

Setup is the #1 killer of geartrains. Unless you are turning things blue from heat, or flaking the hard layer off the gears, lube probably isn't the issue. Usually oem stuff lasts forever, even when subjected to the cheapo oils they routinely use and the abysmal maintenance most people relegate their vehicles to. It's not until you start wheeling them or hotrodding them that things go boom.

I would say the #2 killer is shock loading. No amount of synthetic lube will ever make a 10 spline 1" shaft hold up to a locker and big tires. Same for undersized gearsets. That's why we used to have success with the soft diff gears in drag racing. They would distort instead of shattering.