Differential Fluid

[kball]

I would try greasing the driveshaft. That seems to cure multiple ails on these trucks.

What's it idling at?

 

[rjaudi]

Definitely grease the driveshaft. I would think the universals could cause a problem since the driveshaft is spinning one way and then makes a noise while it transitions to spin the other way.

 

[natevans65]

Amsoil

Check out this site....you can plug in your year/make/model and it will give you all the fluids and quantities for your year. I've found it very useful for replacing fluids throughout my 04 V8 Sport. I ...obviously have chosen to use Amsoil in my 144K mile 4Runner, Lucas-Amsoil.....they are all great products. Just choose one and stick with it for the life of the truck and you should do just fine.

AMSOIL - Synthetic Oil, Motor and Engine Oil, Lubricants, Air Filters, Oil Filters and Greases

 

[Nunyabiz]

He has pretty good rationale after talking to the guys at East Coast Gear Supply. I will let him explain, but it certainly all makes sense.

Then east coast gear supply is delusional.

There is simply zero reason to not use synthetic in your diff, it is a superior lubricant in every way, retains its viscosity much better, breaks down much slower, adheres to the metal much better, keeps the gears running cooler.
Synthetic does NOT get "thin" when it gets hot that is pure nonsense.
Synthetic engine oil retains its viscosity FAR better than petroleum based oil, so why exactly would the gear lube allegedly get "thin" when hot?
Dont buy it at all and used for far too long without a problem to think any different.

Been using it since 1977 without a single issue.

 

[Mano1124]

Ill grease up the driveshaft. I forgot to mention, when I shift throught gears, P R N D, I feel a rough shift through the shifter. Its like I have force the shifter a bit to put into gear. Just weird because its full on tranny fluid.

 

[Singtoe]

Then east coast gear supply is delusional.

There is simply zero reason to not use synthetic in your diff, it is a superior lubricant in every way, retains its viscosity much better, breaks down much slower, adheres to the metal much better, keeps the gears running cooler.
Synthetic does NOT get "thin" when it gets hot that is pure nonsense.
Synthetic engine oil retains its viscosity FAR better than petroleum based oil, so why exactly would the gear lube allegedly get "thin" when hot?
Dont buy it at all and used for far too long without a problem to think any different.

Been using it since 1977 without a single issue.

This is right from Easy Coast Gear Supply's FAQ's.

GEAR OIL: THESE AXLES ARE SHIPPED WITH ASSEMBLY LUBE ONLY. FAILURE TO ADD GEAR OIL WILL CAUSE IMMEDIATE FAILURE AND BE VERY EVIDENT. ALWAYS FILL FROM FACTORY FILL HOLE NOT AFTERMARKET COVER FILL HOLE. We recommend Lucas 75w/140 gear oil, Lucas 80w/90 gear oil is also acceptable. We do not recommend synthetic fluids. IF you have a factory limited slip or any clutch style limited slip a limited slip additive will need to be added. TRANS-X makes a good additive that is available at any auto parts store and we also have it available for purchase.

I got to talk them in a meet and greet a couple months ago. The business is differentials and i don't think that they are delusional about it at all. They have seen it all and when I spoke the them in person, they said the number one reason for diff failure and return was the use of synthetic oil. I don't know how many ring and pinion gears you have installed since 1977 but i am sure they know what they are talking about.

I would have thought that synthetic was the way to go and I used to put synthetic in all my stuff but i have since learned different. Unless the device was specifically engineered for the use of synthetics (clearances, capacities, shear types and temperature range), i would stay with conventional oil and the factory service terms.

Fwiw - I have an Audi Bi-turbo A6 and it requires the synthetic engine oil and it has the Lifetime synthetic tranny fluid. So what is lifetime - for synthetic, My lifetime or the the car's lifetime.

 

[Nunyabiz]

Well thanks for letting me know whom not to go to.

Because saying that synthetic gear oil "causes" diff failure is pure nonsense.

I could not care less what they have to say about it and dont care how many gears they have installed because that statement is simply false.

The only possible reason I could think of that they may be seeing higher rates of failure from gears running synthetics (assuming they are) is probably because people that run synthetics might be harder on their equipment in general and also might leave the synthetic gear oil in the diff for too long, past its useful life.

But claiming that a provably superior lubricant is "causing" differential failure is utter nonsense.
Also it appears as though that quote from that so called "FAQ" is probably referring to the "Break In Period" when brand new.
Gears need to break in, when brand new they run a bit hotter until they fully break in. Synthetic gear oil works so much better that the break in period would be far longer.
If I bought a new truck I would break in the engine and gears with petroleum for about 500-1000 miles before switching to synthetic.

The vast majority of large trucks on the road, everything from 18 wheelers to dump trucks to trash trucks and everything in between that run harder and longer under far more stress and load than a comparatively tiny little 4Runner differential ever will, most all run full synthetic gear oil.

There is simply no logical reason why this place is making this statement.
Synthetic gear oil has FAR higher sheer strength, much better thermal stability, maintains its viscosity far better when hot, does not gets as hot in the first place and keeps its lubricating properties far longer than any petroleum based oil.

 

[Singtoe]

Well thanks for letting me know whom not to go to.

Because saying that synthetic gear oil "causes" diff failure is pure nonsense.

I could not care less what they have to say about it and dont care how many gears they have installed because that statement is simply false.

The only possible reason I could think of that they may be seeing higher rates of failure from gears running synthetics (assuming they are) is probably because people that run synthetics might be harder on their equipment in general and also might leave the synthetic gear oil in the diff for too long, past its useful life.

But claiming that a provably superior lubricant is "causing" differential failure is utter nonsense.
Also it appears as though that quote from that so called "FAQ" is probably referring to the "Break In Period" when brand new.
Gears need to break in, when brand new they run a bit hotter until they fully break in. Synthetic gear oil works so much better that the break in period would be far longer.
If I bought a new truck I would break in the engine and gears with petroleum for about 500-1000 miles before switching to synthetic.

The vast majority of large trucks on the road, everything from 18 wheelers to dump trucks to trash trucks and everything in between that run harder and longer under far more stress and load than a comparatively tiny little 4Runner differential ever will, most all run full synthetic gear oil.

There is simply no logical reason why this place is making this statement.
Synthetic gear oil has FAR higher sheer strength, much better thermal stability, maintains its viscosity far better when hot, does not gets as hot in the first place and keeps its lubricating properties far longer than any petroleum based oil.

I don't hear you praising synthetic fuels. I want hear you run corn alcohol and other Bio fuels. But, that is besides the point.

Your not going to burn gear oil. Thermal stability is not a factor in gear oil. It might get warm but never hot enough to boil off any water. If Synthetic oil was the all cure all, then anybody who runs synthetic oil will have absolutely zero problems and that is simply not true. I have seen Audi's and BMW's with transmission problems where they have worn bearings and syncros and they were using synthetic oil from the beginning.

This is from personal experience. A friend of mine has a 95 Nissan Hardbody and the 5speed tranny drain plug was a bit loose. After a couple of years of driving it, he notice the tranny was making noise, especially when it was in neutral. He wanted to do tranny fluid change and switch it over to to synthetic. I pulled the tranny plug. There was only 5 or so onces left in the tranny. It had all leaked out the loose drain plug. Anyway, I thought the tranny was toast. We put in the specified amount of royal purple in it and the tranny was still noisey. Long story short, I told him to take the royal purple out and use the Lucas gear oil. The noise was cut down to barely noticeable and he is still driving the truck today. So yes, I am a firm believer in Lucas gear oil.

Yes synthetic oil is far superior oil but only in its proper and engineered application. Yes, you have have been using synthetics since 1977 and have never had any issues and yes, I have been using conventional on since 1983 and have never had an issue either. Mind you, that I am using synthetics where the application calls for it.

As for ECGS, they re-gear more diffs in a day then I have in my life so I would have imagined they have seen and tested it all. They offer a solid warranty that is far better then anyone else's in the industry and they wouldn't offer it, if they were going to get a lot complaints or issues with their service. Their only one requirement is the use of non-synthetics.

 

[Nunyabiz]

Well there isn't any scientific basis for such a claim.
and thermal stability (heat) is literally THE leading cause of break down in any kind of oil be it gear or engine oil.
Keeping your engine and gears as cool as possible through heat transfer and less friction is THE purpose of all lubrication so not sure where you getting the idea it has nothing to do it. It has everything to do with it.
and biofuels are not "synthetic" they are simply a different more renewable form of fuel made from corn, grass and what ever else.

I do not recall anyone saying that running synthetic is a miracle cure and if you run synthetic then your engine and gears will last forever.
I have merely stated they are better than petroleum based oils, which they very provably are, better doesn't mean zero problems, zero wear, and last forever, it simply means "better". Its up to the owner to change the oil in proper intervals and do proper maintenance.

Now "Royal Purple" gear oil I have heard was indeed NOT a good gear oil, fair engine oil but NOT good for gear oil so I am sure you are correct in that assessment.

But I actually emailed east coast gear yesterday and got an email today and they basically recommend nothing but Lucas 85W140 which is WAY over what Toyota recommends viscosity wise. He (Chase) also stated that Amsoil he believes is the best synthetic gear oil and it should work just fine.
But it appears to me the main thing for his reasoning is really "Viscosity" more than anything else which is why they recommend 85W140 for as he puts it "cushioning".

He did however make a statement that I know for an absolute fact is totally bogus in his email. He said that he 'believes" that regular petroleum based oil "dissipates heat" better than synthetics which is obviously false.

Synthetic dissipates heat, keeps gears and engine cooler due to less friction, and transfers heat FAR better than ANY petroleum based oil.

I have proven this to myself many many times, the very reason that I started using synthetic oil in the first place was because of a overheating issue in my old Baja Bug VW. I tried everything, deep sump, external oil cooler mounted on the roof under a scoop, every kind of petroleum oil nothing made any difference, it would always overheat when the temp got over 80 degrees and lose lots of power.

I tried 20W50 Amsoil racing oil one day and BAM never overheated again.
That was proof that synthetic oil dissipated heat FAR better than any petroleum.
In my Jeep I just sold the engine ran cooler by a few degrees by simply running synthetic oil.
I have had friends where they had transmission temp gauges and ran synthetic ATF and their trannys ran several degrees cooler.
So this is not a figment of my imagination.
Synthetic is better in every way.

I kind of doubt you will get too many people recommend using 85W140 in a Toyota 4runner diff when the factory recommends 75W90/80W90 for standard use.
My gas milage is bad enough as it is without putting in peanut butter in my diffs.
Not to mention when they heat up, the Amsoil severe gear 75W90 is probably running about the same viscosity as that Lucas 85W140 anyway. The Lucas loses quite a bit of sheer strength when hot where as the Amsoil does not. In fact sheer strength wise the 75W90 Amsoil is better/higher when hot than the Lucas 85W140 is when cold.

As for ECGS I would NEVER buy a diff from someone that recommends nothing but 85W140 and would void a warrantee if you use a superior oil.
Thats just crazy talk and without a shred of evidence to back it up.

That is kind of like the Young Earth Creationist of the Gear world, facts mean nothing, just belief.

 

[Mauzer]

Interesting thread, I know lots of people who love ECGS and I recommend them to people b/c of all the great stories I hear about their setups and service...but I also know that all the people I wrench w/ (including people who get their diffs setup from ECGS) use 75W90 Redline Shockproof.

Lots of good info and could be a great debate if we could get some science behind ECGS's suggestion of no synthetics? I'm def going to keep running redline shockproof though

 

[Singtoe]

You still haven't provided a shred of scientific basis for your claim that synthetic kills diffs. So does the shop ask all the owners how long synthetic has been run, consider the odometer, know how the vehicle was used, know how many owners it had, checked the fluid level, know the proper weight was used, have any scientific basis whatsoever for their claim? <-- not yelling here, just emphasizing my main point. There are far too many unknowns for you to make a claim that synthetics kill diffs.

Just because one shop that does diffs all day believes something doesn't make it true. Back up your 'factual' claims (I'm a science guy if you haven't figured that out yet If I go hunt down a shop that does diffs all day and they say using synthetic is better than conventional does that mean it's true? Nope.

Not saying you are wrong, but you haven't backed up your claim and probably no one is in a position to. I have not read a single thread about a 4Runner running synthetic that failed before its time (seems like most members here run synthetics too). If synthetic did kill diffs, I'm sure there would be multiple threads here about people with that problem. I could hypothesize that people who run synthetics are more dedicated to fixing their vehicle than others and take better care of their vehicles (so they have a longer lifespan) and therefore it is more likely their diffs see more miles and inevitably will need fixed. Or perhaps they are more likely to wheel their vehicles, and while they run synthetics, the wheeling is the real cause of the failure.

For your Audi & BMW statement. If they have run synthetics from the beginning I have to ask if they were factory-filled and engineered for synthetics. If they were, couldn't the problem be related to engineering design rather than the fluid?

I see this claim as similar to your claim that our ball joints suffer from an engineering defect. If that were true, our ball joints would be failing with fewer than 150k on them. Instead, the only 4Runner failures you see are on lifted, heavy bumper, 150k+ 4Runners...hardly a defect.

Stick to your opinion, but state is as just that...not a straight up claim like it's fact.

That is the beauty of Forums and it is my opinion. And when you see a doctor and get his prognosis and don't like it, what do you, you get a second opinion.

When people type up a question; Opinions are what we get.

My airbag light is on? My opinion was to check the clock spring.

My antenna is making a racket when going up. Most opinions where to replace with a Taco whip but my opinion was just to replace the mast.

What kind of diff fluid to use? The FSM calls for a Hypoid Gear Oil GL-5 SAE 75w-90. It is someone's opinion to use Synthetic

What size socket to use on front axle stub - The size measured with caliper says 35mm but it is my opinion to use 36mm because it will fit the new nut and will fit most other axle nuts you might come across in the future.

What brand tire to get? what size? -- All opinions

Should the White lettering be outside or inside- 3/4 of the people who voted opinion's were to put them on the inside.

There was a typo in the FSM on the torque specs for the 8mm diff stud and nuts. It was my opinion who said it was way too much. Did I write the FSM? Do I memorize the torque specs for 8x1.25 bolts?

And yes - it was my opinion, that the ball joints on the 4runner and Tacoma are engineered to fail. But that is my opinion and i am sticking to it. There was even a recall on the later 4runners because of poorly manufactured ball joint. So what is the difference between a poorly manufactured ball joint and one that has 100k miles on it? Sure ball joints wear out but at the worst, they should cause poor handling or bad tire wear - Not catastrophic failure causing possible death, severe trauma and total vehicle loss.

So every reply on a forum is an opinion - Take it for what it is worth.

So getting back to OP question, I trust the opinion of not only the local rear end shop but rather, the nationally recognized rear end shop with a 5 year warranty behind their service and products. And yes- I can not provided a shred of evidence to back this opinion up other then fact of their real world experiences and the feedback that they have from using their products.

It is my opinion that Synthetic oils are not the cure all for all lubricants. Cars and trucks that use Synthetic still fail and are still being worked on in the dealerships. It is what it is.

 

[Nunyabiz]

It is my opinion that Synthetic oils are not the cure all for all lubricants. Cars and trucks that use Synthetic still fail and are still being worked on in the dealerships. It is what it is.

That is fine, however I believe it was your opinion that "synthetic oil will kill your diff". Unless I am mistaken and misunderstood.

Once again nobody anywhere has ever stated that synthetic oil is a "cure all" thats nonsense, of course it isn't.
Nobody has ever even insinuated that if you use synthetic that you will never have a problem with your engine or gears.
Again that is a ridiculous statement that I cant believe anyone would ever make.

But so is saying that synthetic gear oil will kill your differential and ruin your gears.
Especially considering the FACT "not opinion" that synthetic oils are far superior in what they do which is lubricate.

If anything I could see having a problem from using far to thick of a gear oil (Lucas 85W140) than I could see using the recommended viscosity in Synthetic oil. I would think that Toyota recommended 75W90/80W90 for a reason.
I suppose its possible they did so just so you would get better than 10 miles to the gallon but I don't know.
I do know that 75W90 Amsoil FAR exceeds what the manufacture says is needed though.


I somewhat agree with you on the ball joints, not so much that they were "engineered to fail" I kinda doubt that but I do think they definitely had design or quality control problems in at least a few model years, mine being one of them because the previous owner had these ball joints replaced about 65,000 miles ago through a recall and they did it for free at the dealer. They would not have done that unless they admitted to a flaw.

 

[Mano1124]

So, i took it to my friend that is a mech and he told me that the drive shaft doesn't need to be greased up. That the jerking of the truck when switching to reverse and drive is normal. It's not normal. I have a 4runner and it does not do that but it's starting to feel like the shifter is being a bit forced into gears. Any suggestions?

 

[Singtoe]

Find another friend.

 

[Nunyabiz]

Kinda sounds like a Ujoint going bad.
Maybe a lose or missing tranny/motor mount bolt?
Carrier bearing?
I think there is also a tranny fluid pump that might cause something like this if it starts to go bad, but not sure.

 

[Tomsriv]

Just to throw fuel on the fire, what I took away from the differential guys is that you don't put synthetic oil in when it is new because it won't break in properly. The same is true for an engine. You never put synthetic oil in a brand new motor. Fortunately modern engines are broken in before they leave the factory.