This matches the guide that came with my 2008 F-150.

https://www.fordservicecontent...guides/08frdmg3e.pdf

Even if these fluids don't lose their lubricating qualities, who's to say, with this old truck with unknown past, they aren't contaminated? Better safe than sorry.

If this truck has the 5.4 3-valve engine, it falls within the year range of the infamous separating spark plugs (if they are still original). Speaking of spark plugs, iridium plugs can in fact go 100K, even more. My Toyota specs them at 105K. I did them at 110, and there was very little wear on them.

Every lubricated gearcase has break in debris. Maybe owners should care about it even if the manufacturer doesn't. I did my 2003 Silverado fluid by transmission cooler line exchange with TES 295 fluid at 25 and 50 thousand miles. 12 quarts pumped through until new fluid appeared. It now has 60 thousand. I did diffs at 25 thousand, front that rarely gets used had some moisture in it. I replaced a plastic vent fitting that now allows synthetic fluid. Transfer case gets a couple of quarts of ATF, so its been done 3 times in 60K miles.

My brother did the transmission fluid and diff in our BMW at 50K when he owned it before us.

I purchased a Ford F150 XLT 4X4 new in 2004. Factory maintenance instructions included draining and refilling the automatic transmission and transfer case at 50,000 mile intervals. I always had them do the differentials as well.

12 years and over 170,000 miles with very few stops other than regular maintenance. Very good truck.

All I can tell you is my experience. My 2010 Tundra has a "sealed" transmission. There is no dip stick so no fill tube. After 150,000 miles, I noticed a difference in shifting. It was slight but there. So I researched how to service it, bought the equipment and drain/filled three times. On the third drain there was no detectable color change in the fluid. The first drain was very dark almost brown.

I know Toyota says these transmissions use a lifetime fluid and that's why they are "sealed", but after I completed my service, the trans went back to smooth clean shifting. Now I drain/fill once a year. Probably worth it for others to service lifetime fluids too.

A very smart skilled tradesman that used to work for me said this about "lubed for life" bearings:

"When it fails due to lubricant breakdown, it reached it's life".

I always interpreted lifetime fluid as in length the component the manufacturer warranties it for.

ok, now tell me how to check my transmission fluid on my 2020 Chevy 2500HD. i know it's probably fine but I do not like not knowing. i've always checked and topped off my transmission during oil changes.

Is there a service manual that's not top secret?

quote:

Originally posted by darthfuster:
All I can tell you is my experience. My 2010 Tundra has a "sealed" transmission. There is no dip stick so no fill tube. After 150,000 miles, I noticed a difference in shifting. It was slight but there. So I researched how to service it, bought the equipment and drain/filled three times. On the third drain there was no detectable color change in the fluid. The first drain was very dark almost brown.

I know Toyota says these transmissions use a lifetime fluid and that's why they are "sealed", but after I completed my service, the trans went back to smooth clean shifting. Now I drain/fill once a year. Probably worth it for others to service lifetime fluids too.

My Tacoma has that same design. I miss a dipstick. Now, you have to wait for the appropriate “steady trickle” to see if it’s filled to the correct level.

4MULATOR do you work for Ethyl Oil?
The reason I ask is I built a home for the guy who used to run their lab and I learned a lot from him. His name was Ron S.

I'm not speaking for big rigs, bulldozers and the like. But for daily drivers and light duty work trucks, I flush 100% of all my fluids - tranny, engine coolant, brake fluid, power steering fluid, differential gear oil, the whole nine yards for ALL systems with fluids, no exceptions. That way all those systems have the maximum chance of running well for as long as possible. It's just common sense to me. You can do most or all of that yourself if you enjoy that kind of work and don't mind spending a little money on decent enough quality DIY level tooling.

On the other hand, if you don't keep your vehicles a long time, or don't care about the reliability of those vehicles that you do, then don't complain about replacing components and systems after they've been destroyed by internal pollution and corrosion and accelerated wear.

Think of this as an example - most people don't think about power steering fluid. But pop off the cap, and draw some out with a straw and drain it in a clear glass container. It's brown or worse, black. That fluid is oxidized, acidified, and contaminated with dirt, metal particles, and who knows what else. Some mechanics call that cutting fluid. I agree. Don't want power steering fluid leaking all over your driveway ? Then flush that shit out 100% and replace it. That's just one example. All system in a vehicle that run fluids are damaged to some degree by old fluids.

Besides fluids this rule also applies to limited lifetime components. Filters, pcv valves, EGR valves, coolant hoses, transmission hoses, serpentine belts, tensioners and pullys etc. Those guys don't last a "lifetime" either. When those guys go your car stops and you're stuck.

If you replace your vehicles before they get age on them fine. But if you keep them like I do, you may expect to break down from time to time, sometimes in the worst times and locations that you'd rather not think about if you ignore that stuff, or think that changing your engine oil is the only thing you need to worry about. Though the engine oil is the most important one to pay attention to, it's not even close if you want reliability, performance, and good mileage.

My Jeep Patriot has fluids that claim to be lifetime or have extremely high change intervals. Jeep Patriots are known for having transmission issues. My research indicated that owners who changed their transmission fluid at 50k intervals rarely had the failures and overheating transmission issues that the majority of Patriot owners eventually experience.

Like others have said, no fluids last forever. I think that manufacturers figure the junk that is being put out now-a-days won't outlast the fluid they put in it. The Fords we drive for work are lucky ro get 60k without major replacements (engine, transmission, ecu...).

Our Flex says the same for the transfer case or power transfer unit or whatever they call it, it is full time AWD. Same setup for some explorers. The change interval for the Explorers used by LE call for transfer fluid change at 30K, which is odd, since mine is the same, so I follow that schedule and change it out every 30K. Bought the vehicle with 40K on it and it did look a bit rough, but that is just looks and no scientific basis to back it up. $40 in lube is a nice insurance policy to me.

quote:

Originally posted by mrvmax:
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.

I agree. I think "lifetime" means 100K miles to these folks. They want you to buy a new car.

Oddly enough my coworker took his Chevy truck with 33000 miles in to get worked on due to auto Trans problems. Today the Chevy dealer replaced that lifetime fluid and said they are seeing moisture get into the sealed transmissions causing shifting issues.

The moisture in the transmission causes an irreversible reaction with components within the ATF additive. There is always water within the fluid, created with acid-base reactions over time, resulting in water in the parts per million range. But, excess water does affect the ATF. As a contaminant, causing undesirable reactions, there is no solution other than to change the fluid and stop the water vapor and road splash water from entering.