Rear diff fluid at 1k

The bicycle comment was funny because avid cyclists debate on things like chain lube vs wax, grease vs oil, tire size and correct pressure etc.
On forums filled with enthusiasts, you can count on people making the simple become horribly complicated. As an avid cyclist, I almost want to say that the bicycle forums are even worse than here.

 

Just a quick Google search:
https://www.thecarconnection.com/news/1092906_do-you-still-have-to-break-in-a-new-car

The only thing broken in on a vehicle is the engine, the piston rings specifically. That is done at the factory.

Ever wonder why Toyota never says to do an oil change at 1000 miles or drive below a certain speed for a while? Yet, Toyota is still extremely reliable. maybe they're on to something?

 

If you ask your A&P mechanics that keep your helicopters in the sky, they will tell you that they don't do anything aside from exactly what the manufacturer says. If there's an early oil change then there is a specific reason why, usually because there's excessive debris found during routine maintenance.

 

These are the same people that didn't provide a transmission dipstick... Then underfilled them from the factory. ..

 

...^^^... Good point. I do know that the mechanics hate dust and sand.

I am just a weekend DIY guy on my vehicles and I would change the lubricants all the time if I could.

My 2016 Tacoma has about 23,000 miles and is 32 months old ... have changed the oil and filter about every 6 months.

I will probably do the rear diff soon.

 

good point

 

Is there a history I don't know about? The transmission realistically doesn't need a dip stick. You'll have more people getting scared over meaningless metal on their dip stick and wanting to change fluids too often.

I used to work at a transmission shop a while back. Most transmission issues came after someone wanted to change their fluids. Automatic clutch packs need to keep some of the debris in between the clutches in order for them to grab. Flush the transmission and you further erode your components.

I'm not saying engineers are perfect, they're human like the rest of us. But there's a team of them that say there's a way to do things based on their design and testing. I would trust them more than my knowledge of machines and definitely more than a garage mechanic who wants to "baby" their truck.

 

Mostly because dust and sand erodes the paint on the rotor blades and gets in all the little nooks and crannies in the sheet metal. It makes cleaning and taking care of the birds much harder. Dust and sand doesn't really affect the engines too much except for turbine engines. Turbine engines in dusty areas get special maintenance since the dust and sand heats up on the combustion blades and makes a mess of things... Still nothing to do with the oil.

 

I own MobilExxon stock. Please change all of your fluids regularly. At least every quarterly dividend if possible.

 

You can’t blame the engineers though for the failure of assembly.

 

My standard practice on every new vehicle I've ever purchased is to do a complete fluid swap (engine oil, diffs, transmission and coolant) after the initial break-in(typically done within the first 500-1000 miles) and then following somewhere between the factory recommended extreme/standard interval swaps depending on the severity of use.

Overkill? Maybe... but they almost always drain with some metal/sludge/other contaminates after the break-in. It's certainly cheap insurance in my book to ensure maximum longevity of the most important parts of a vehicle. Considering I've had multiple vehicles still running strong with 300+K on the clock, I'll continue the practice.

And for what it's worth, I am a mechanic (aircraft) ...

 

Here is the answer on when to change your differential fluid:
It depends, which means there is no correct answer that is all encompassing for everyone.

Differentials are not exposed to contaminants like engine oil, excepting the actual gear wear particles. That's not to say you can't introduce contaminants (water) into the housing. If that happens, all bets are off.

In normal use, the only thing you have to worry about is fluid shear. This is caused By the more viscous fluid's particles rubbing together which causes friction which causes shear. Now, newtonian fluids shear all the time. It's inherent. In the case of our differentials that fluid needs to be changed sooner if you run the dog shit out of it or if you tow heavy a lot.
Personally, with my driving style and use, I change it every 50K. Some might need to change it every 20K if their use is hard on the truck. Maybe even 15K, but no sooner because most any reputable synthetic will go that long in a differential.

Since the only thing that will mandate a differential fluid change is fluid shear (excepting water in the diff) then changing any earlier than 15K is totally unnecessary. However, if you want to change it every 500 miles, knock yourselves out. It's simply not needed though.

Here are some links, heavy and light:
http://www.homepages.ucl.ac.uk/~uceseug/Fluids2/Notes_Viscosity.pdf
https://en.wikipedia.org/wiki/Shear_stress
https://blog.amsoil.com/how-often-should-i-change-front-or-rear-differential-fluid/
http://www.themechanicdoctor.com/how-and-why-change-your-differential-fluid/
https://oards.com/differential-fluid-change-interval-and-cost/

For the record, I have been around engineers, engineering techs, Phd's, mechanics and service personnel for the past 30 years. Nowhere have I ever heard nor read that it is necessary to change fluids on a brand new vehicle or machine. UNLESS, the box is so custom built that it is a prototype or a one-off. Then you need to change it early for test. Oh, If I were going the "regear" route in my truck I would absolutely change it at 1K. For OEM mass production stock gearing it is just a waste of time and oil. My opinion, but there is about a zillion documents to back me up.

 

All that sounds good. However, Toyota wants you to get outside warranty. After that its your problem. They don't want it to last hundreds of thousands of miles. They would not make the money. Its not just Toyota it's all of them.

 

I attempted a hard break in on mine to see if I can get above average fuel econ/power out of the engine.

 

get a Blackstone UOA test done on the oil if you really need to know what condition its in

 

So you only break in used older vehicles? Lol. My head hurts.

 

There is a big difference between saying:
"Changing fluids early is not needed in a new vehicle"
And
"Changing fluids early does damage in a new vehicle" as svdude states.

I wont argue the former but there is no evidence I'm aware of to the latter. If there is I truly want to read it.

 

I changed my diff oil to Redline 75w85 at 5000mi.
Nothing out of the ordinary in terms of oil color or metallic particles... I'm sure it could have went 30-50k miles without much change.
I just figured that if I'm going to spend the $90 bucks for synthetic gear oil, I may as well spend it up front since I'll likely only change it a few times in the life of the truck.

Edit: Found out the OEM gear oil is full synthetic...

 

Wow I did the changes as Toyota suggested and I only have a hundred and fifty K on the truck should I be concerned? The last two only lasted about a 300K before I sold them.

 

http://i.imgur.com/Gnro6.gif