4th Gen Maintenance Questions

Oil changes are important on direct injection gasoline engines. Fuel dilution can occur which will lower the viscosity of the oil and can harm internal components.
I never wait for the factory light to go off, I try to change the oil every 5,000 miles. Make sure if you do your own oil changes to use a Motorcraft filter, the way the oil filter sits it has a back flow preventer to prevent the oil from constantly draining out of the filter.

This may sound overkill, but I push the gas pedal to the floor and crank the engine before startup which prevents the engine from starting, but you will see the oil pressure gauge move upwards to prelubricate components before the engine starts.

Not something people are going to do, but being an engineer I can tell you the hardest and most wear on an engine occurs on startup and if all the components have no oil on them it will increase the wear.

Transmission and differentials I would do every 30,000 with heavy towing and 60,000 with minimal to no towing. I followed these intervals on my jeep grand cherokee and I am proud to say I have over 650,000 miles (original engine, transmission and differentials). Oil doesn't break down, but the additives do which is why it is important to exchange fluids as time goes on.
Brake fluid gets flushed at 60k and replaced, coolant I always did between 80k and 100k.

The manufacturer recommendations are a general reference. Only you will truly know how you use the vehicle and the environment you run in. Sorry this is all overkill, but just giving you my opinion.

I also send oil analysis out periodically, sending an oil analysis out on transmission and engine oil can give you a good idea on what is happening to the fluid as it ages as well as a way to monitor for potential issues. Once you start building a trend you can tell by looking at numbers if something is starting to wear out internally in the engine somewhere.

Dice Roll said:

Are the plugs hard to get out of the heads on the 3.5? I’m always concerned on late model stuff about pulling threads out, etc. Seems some fords were a problem hold with a weird plug that captured carbon in the early 2000s.

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Dice Roll said:

Are the plugs hard to get out of the heads on the 3.5? I’m always concerned on late model stuff about pulling threads out, etc. Seems some fords were a problem hold with a weird plug that captured carbon in the early 2000s.

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The plugs are actually very easy, not like the older Fords with the two piece spark plugs. When I did mine at 60k they did squeak when hand turning out but no drama. They come from the factory with NGK plugs which are very good and not known to becomes seized easily. I’d say don’t worry.

Oh good. Ngk is my preferred brand after trying all sorts over the years. Thanks.

Dice Roll said:

Oh good. Ngk is my preferred brand after trying all sorts over the years. Thanks.

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Best bet is to get them from the dealer. There’s a lot of fakes on E-bay and Amazon that cause all kinds of problems.

I'm slowly becoming comfortable working on the Expy. I tend to do tons of research...only to find that it ain't that hard! Not many videos for our vehicles out there, and the F-150 info is helpful but not always the same.

Plugs: bought NGKs from Rockauto for a great price. I think it took me an hour. Big take away in case you're new to working on vehicles: sometimes in tight places, you gotta put the socket and extension on the plug, then attach the socket wrench. Anyway, easy for someone who has wrenched, but bring a step stool. Dealer wanted $550. I did it for around $30.

Rear differential: also easy, though I highly recommend getting a fluid transfer pump ($10 at the auto parts store). Access to the fill plug is too tight to use a squirt bottle. I'm running 2.5 quarts of Valvoline 80W-90. Dealer wanted $200. I did it for $30.

Downpipes: you can find my post on the SPD installation elsewhere, but this job takes someone in an F-150 about 3 hours. Took me 6. Nothing was seized fortunately, even after 100K miles. But it takes lots of squirming, twisting, cussing. I recommend having a buddy to help and keep you sane. And mechanics gloves to save your hands. Dealer wanted $1,900 to replace one cat; I replaced the whole downpipe assembly for $850, then got $300 for my old unit.

Brake pads: easy and quick.

Transmission fluid change: scares me. Changing to a metal oil pan doesn't look fun. Transfer case and front diff next.

I don't have my new expedition yet but coming from a first gen F-150 Ecoboost I can attest that new plugs do wonders with these engines. Also check the gaps before you install them.

Low maintenance is a big selling point to people that are clueless on cars. They buy based on how cheap they will be to maintain. So I'm sure Ford stretches those numbers to make them look better to those buyers.

Regarding the rear diff fluid (I have the eLSD rear axle), I changed the fluid at 17.5k miles while chasing a faint gear whine that happens at 75 mph in hot weather. The fluid looked really alarming with what looked brown/green paint mixed with silver paint. I sent an oil sample to get analyzed, see the results below. The comment from the lab read as follows: "It's not unusual to find a little visible metal from break-in, and as long as it's not excessive and clears out on its own, small amounts aren't necessarily a sign of trouble. This looks like it's the differential's first oil change, and we expect to find some extra wear metal on a microscopic level in those cases as well. Chrome, iron, and copper show harmless wear-in material related to break-in. That should clear out further with more oil changes, and then we'll expect metals to look more like Ford differential averages (which are based on ~36,500 miles)."

I will do my next diff fluid change in April and will send another sample to get analyzed. Although the comment from the lab states that it is OK to have these metals, I was happy that they were out of my rear end haha.

This thread is great and really the only place online I’ve found anything about maintenance care beyond the overly extended or non-existent numbers in the manual. Any recommendations on how often coil packs are recommended to be changed? Should I probably be looking at a brake fluid flush at 67k miles? Also planning on plugs, ATF, and T-case fluid changes soon.

We just bought our 2018 Expy and while it had consistent oil changes, not much else has been done yet, so want to get it back in a good spot for longevity purposes and just to reset what might need it at this point. Thanks for any opinions.

Just had my dealer do transmission service as preventative maintenance at just under 80k miles. On the parts list is TFK Trans Flush, so it appears they did some type of flushing.
Wow- Driving the truck home from the dealer, transmission shifted so smooth. Glad I had this maintenance performed. The owners manual recommends fluid replacement at 100k miles.
BTW- I have not had any transmission issues. Yes, I have had perhaps three rear diff clunks from transmisión not optimally shifting over 79k miles of driving.