I recently bought a low mileage 2008 F150. I talked to a mechanic friend and asked him to change the oil, do a drain and refill along with new filter on the transmission, and change the oil in both differentials and the transfer case.

He started digging into it and told me that the transfer case and both differentials have fluid/oil in them that’s supposed to last the life time of the vehicle and it says not to change them if they aren’t leaking or there isn’t a problem. I think I know the answer to this but would you all trust that? I kinda got the feeling he didn’t want to mess with those. But I could be wrong and he actually believes the oil is still good in them.

No lubricating fluid lasts a lifetime - none. It will last the average lifetime of the first buyer before they trade it in. Auto makers know that, the less money the original buyer spends the more likely to buy another new car. They are not worried about the second and third owners.

Lubricants get contaminated and additives deplete. Nothing they auto makers do can prevent this for the lifetime of the vehicle. If there were lifetime fluids major companies (Shell, Exxon, Chevron) would never change fluids in their equipment, they would use lifetime fluids, but there are none. They have schedules to replace, sample and analyzer fluids.

No fluid lasts a "lifetime." I'll wager the owner's manual maintenance schedule does tell you to change them at some point, especially if subjected to "severe" service like towing, dirt roads, etc. Transfer cases are a simple drain and fill, with plugs for both. Differentials, if equipped with a drain plug (the rear probably isn't but the front might be), likewise. If not, the covers can be removed to drain the fluid. This is pretty simple stuff. The automatic transmission is not so easy. The pan can be removed and the filter changed (but this doesn't drain the torque converter, which holds over half the fluid), and/or a fluid exchange machine can be used. Filling it is another story. This is the transmission fill plug and dipstick.



The truck has to be put on a lift, the plug (next to a hot exhaust pipe) removed and the fluid pumped uphill somehow. Pumping ~6 quarts with a hand pump will wear your arms out. There are special filling devices available, but are high priced. Alternatively, rig a long hose and funnel and pour the fluid in from topside. Since the hose has to be narrow enough to fit down the hole, the fluid must necessarily be added very slowly. There are much easier ways to make a living. At least be thankful you don't have a Chrysler 8-speed.

Ford probably expects/hopes the lifetime of the truck is a lot shorter than you're hoping for.

What Ford says is not necessarily what the makers of their transmission recommends.

BMW says the same nonsense: transmission fluid is "lifetime". However, ZF, the manufacturer of said transmission, actually specs 60,000 mile change intervals.

I haven't quite added the claim of "100,000 mile spark plugs" to that list of what I believe about various automotive theories.

"Non-change fluids" is just too far down on the chain of likelihood for my past life of automotive reality.

On the other hand the more recent assertion such as air & fuel filters needing change only when demonstrated dirty by inspection. Checking my 24k 2020 Ranger seems to be supporting that claim. For now I insist on oil filters with the new oil.

You don't say how many miles you have on that F150 but I am guessing you have well over 100,000. I would change out all of them. It is a pretty straight forward job except for the transmission. As mentioned above, you will need a fluid exchange pump to get it all out.

I’m guessing the real question is regarding gear lubricants, in particular, differentials.

I drive semi trucks. I own semi trucks. Nobody in the industry is running conventional lubricants in gearboxes anymore. In fact, manufacturers like Spicer and Eaton will only honor warranties when synthetics are used.

In our industry, manufacturers recommend a change interval of 750,000 miles for differentials. Most people I know change them at 500,000 just to be on the safe side of things. Maybe simply because 500K is such a nice round number. It soothes the mind.

If big trucks, which would certainly be considered severe duty compared to a pickup truck, can run a half million miles on its lubricant, why would a pickup need to be changed more often? Being that the service life of a pickup is usually significantly less than a half million miles, it would seem that a claim of lifetime lubricant is justified. Furthermore, in semis, the gear lubricant is also servicing the wheel bearings, which is not as common in modern light duty trucks. Certainly not with half ton trucks.

I pulled the cover and replaced the fluid in my 1995 C2500 at 165,000 miles simply because it wasn’t factory filled with synthetic. The gears looked brand new, even with conventional gear oil. I filled the differential with synthetic and will probably never change it again.

ETA:
The only reason I can think that semi truck lube lasts longer is because the operating time is significantly longer. The truck often operates for eleven hours continuously. Perhaps the oil gets hot daily and is better at evaporating out moisture. Just a thought.

quote:

Originally posted by Bassamatic:
You don't say how many miles you have on that F150 but I am guessing you have well over 100,000. I would change out all of them. It is a pretty straight forward job except for the transmission. As mentioned above, you will need a fluid exchange pump to get it all out.

87k and some change.

I’m going to go ahead and change the fluids, using good synthetic oils. It seems like cheap insurance to prevent a major issue. The post about the semis does make sense though.

I have a mechanic do any major work on my car that I don't want to do. I trust him. According to him the government pushed auto makers in making such claims to reduce 'waste'. He also totally disagrees with that you should not change those fluids, he claimed many failed transmissions that never use to fail when the fluid was changed every 60k miles. He showed me an article some auto repair magazine that echoed what he told me.

My cars are Volvos, and my mechanic has been running an independent repair shop specializing in Volvos for over 30 years.

Check out this video

https://www.youtube.com/watch?v=WaPJJ3hUHN0

My indep. BMW shop won't change the tranny fluid on cars with 80k or more miles. By then you're better off just taking your chances. I just had him change mine at 67k miles. Not cheap at all, but I just wasn't going to buy the tools and DIY it in the 115 deg. heat in my garage.

For 18 years I formulated axle lubricants. The additives were produced for OEMs and oil companies.

The lubricants are designed to last the life of the truck. A very long time. The lubricant in your axles, not made by my company, are fully synthetic and have a very robust additive. The qualification tests for your truck, in which the lubricant is evaluated, take two years to complete. In one lubricant test, the axle is subjected to thousands of miles of maximum weight trailer load launches, repeatedly, followed by high speed low load, then moderate speed moderate grade, then low speed severe grade. Thousands of miles. At temperatures over 95F. In the desert. With full rated trailer load having a large aerodynamic resistance. I personally tested our lubricant against your lubricant there, for 30K miles. There were no failures.

Now, does such testing without failure mean that the lubricant remains pristine? Of course not. Oxidation occurs, and irreversible chemical reactions consume the additive components. The lubricant viscosity increases, somewhat, due to oxidation, and reduces, somewhat, as any polymers within are sheared in the tapered roller bearings. Metal debris is carried around, and increases in quantity over time.

Changing the axle lubricant requires removal of the axle cover, most often. Drain plugs are not fitted to light duty truck axles these days. You can suck the lubricant out of the fill hole, but that leaves a little old lubricant inside. Removing the cover means scraping the sealant off the flange and properly installing a new bead of sealant. You do NOT want the sealant to be mushed into the axle housing interior, as it will create a foaming condition in the lubricant.

If your axle has a limited slip mechanism, you also must replace the limited slip friction modifier. For Ford, this is named M2C118A. It is a vile amine, and will hurt your eyes. You must leave enough room in the axle to add one full bottle, so it is best to put it in first, then fill with lubricant.

Regarding your transmission fluid, it was formulated by my company, and we have supplied it for many years. It is tested quite extensively. Mercilessly. For years. Our additive, blended by the oil company in a high quality Group III base stock blend, is qualified for the life of the vehicle. Its antiwear, extreme pressure, and friction controlling additives are studied and evaluated for years. The chemistry is chosen for a balance of performance and life. Oxidation tests are high temperature and long duration. Friction tests on the clutch packs are thousands and thousands of application cycles. Pump wear is checked. Gear pitting is studied, and none is permitted. Seals are immersed in the fluid, and their degradation is measured. Years of work for a given additive and base oil system.

Changing your ATF requires either a few drain and refills, or an exchange pump. People argue about these methods. Drain and refill with a new filter and gasket is certainly a more moderate approach. It can be a bit of a challenge, for 4WD, as the transfer case and crossmember and exhaust may have to be removed. The exchange system is often filled with the lubricant chosen by the shop, and is probably NOT OEM quality. You can’t afford to have them drain and refill the exchange pump tanks just for your job.

Change fluids in a low mileage truck? 2008, now 14 years old, and probably close to 100K miles…yes. Do you need to exchange fluids? Not really. Your vehicle use application is no where near the extraordinary testing each receives. Will your vehicle be better with new fluids? Absolutely. Will new fluids magically repair any metal gear or bearing or friction plate damage? No. Should you change with fluids other than OEM? I don’t.

Do I change my fluids, on used trucks that I own? Yes. But, I have a lab, technicians, extensive testing equipment, and a reason to drain the fluids for analyses of real world data.

In your situation, I infer that you would prefer the fluids to be replaced, and do not believe a fluid can be lifetime. Two things can be true at the same time. The fluid is a lifetime fluid, and changing the fluid will benefit your truck. Choose the right lubricant, and ensure that the shop knows how to change it properly. I would watch the work being done, given a shop’s reticence to do the work, or find another shop.

To quote Judge Chamberlain Haller in My Cousin Vinny, with slight deviation, “That is a lucid, well thought-out, intelligent” post. Thanks 4mul8r.

Consider a brake fluid flush/exchange as well. Brake fluid doesn't wear out, but it can and does get contaminated. Easy job with a pressure bleeder.

I bought an 1996 Dodge Ram diesel 4x4 new and put a lot of miles on it.When I hit 200k I changed the frt and rear differentials that had factory synthetic in them and the fluid I drained out looked as good as what I put back in them.

I'm a stickler for following the manufacturer's suggested fluid changes - within reason.

2008 Ridgeline has about 365K miles
2008 Ford Expedition has about 203K miles
I have a diesel vehicle for work/highway driving and following those German recommendations. Hope to get the same or more.

quote:

supposed to last the life time of the vehicle

Engineers don't make statements like, 'the lifetime of the vehicle'

Marketers, now.....

Someone has a number. Might be a good long number, and you may well be under that number, but I'd suggest you dig in and find that number for yourself, and not depend on a shop who will just nod their head at whatever the factory tells them.

A video from Scotty Kilmer says they mean the expected life of the component. So you may find the transmission has an expected life of 70K miles So change fluid then.