My 2018 6.7 SRW is approaching 60,000 miles, I bought it with 15,000 miles on it. Always changed the oil and filter every 3000 miles, fuel filter every other oil change. When should I change out the other fluids?

 

I d a complete drive line service at 50k. Brake fluid should have already been done a time or two but probably wasn’t so I would do that as well.

Bob

 

Transmission fluid drop and refill with filter change.

 

You should be performing transmission drain & refill every 35K miles or so (install a pan with a drain plug, like the PPE). Also should be doing doing rear differential fluid change (again, PPE pan with a drain plug), front differential fluid change (R&R with a hand pump), and transfer case fluid R&R at the same time. A complete brake fluid change is good around the same time as well.

FYI: You wasted a bunch of money doing oil changes every 3K miles. A BUNCH.

 

Coolant and brake fluid, due to time.

Would be a good idea to do the rest of the driveline too.

3,000 is too early on the oil. I would extend the fuel filters too. It doesnt hurt to do anything early but no reason to open them up and risk contamination if not needed.

 

WOW! Beyond belief that you would be doing oil changes so often and fuel filter changes too!!!
You obviously have too much time on your hands, and money too.
I suggest you read the owner's manual for the maintenance schedule.
You really can't go wrong doing it by the book.

 

unless we are on the severe duty schedule.....severe duty = towing or high idle time or lots of stop and go driving ( metro driving with stop signs or traffic lights every other block, etc).

 

So 2500 of the 3000 miles I’m towing a 6500 pound TT, rest of the time is city with a few 50-75 mile trips tossed in. I can stretch out the oil changes to 4500 I guess. Sounds like it’s time to change/flush whatever’s wet.

 

Same can be said fo 35k mile transmission fluid.

 

For that light use, you could double or triple the oil change miles, so long as it is in a year or less.
As I said, follow the owner's manual, save you time and money.

 

You're not wrong for doing things the way you're doing them. Here's what I recommend for every customer and practice myself for all 3 of my diesel trucks:

Every 5,000 miles- Oil and filter change
Every 10,000 miles- Fuel filter change
Every 15,000 miles- Air filter check and change
Every 30,000 miles- Transmission pan and filter service

This type of service interval has kept my personal vehicles, fleets, and individual customer vehicles running and only coming to my shop for maintenance or something else.

One specific reason why I tell my customers 5,000 miles on diesel oil changes is because of fuel dilution. Part of the regen process is over fueling this time on all 8 cylinders not just the cylinders 7 and 8 on the 6.4 Powerstroke. Fuel can sometimes dilute into the oil and the oil isn't exact how it was designed anymore. Over time, this leads to bearings and critical engine components slowly wearing to the point of failure. Oil changes every 5,000 miles are cheap compared to the cost of a new long block from Ford, not to mention the labor to R&R.

 

I lean more toward longer intervals especially when using synthetics. Sure you can change oil, fuel filters, driveline fluids every 1000 miles if you wish but my feeling is technology wins as usual and there is no need to do it at shorter intervals unless you live in extreme, cold or hot maybe dirty, environments. We are not talking old toilet paper roll oil filters or conventional single weight dyno oils.
IMO at the minimum follow the manufacturer recommendation for change intervals and use synthetics.

Mike

 

I have been going 7500-ish miles (between trips as close as I can) with my ‘24 F-450 that sees most of its miles with the big fiver in tow, last change was slightly over my target mileage but the OLM was still at 15%. What is your opinion (I do value it! ) on the newer trucks with the 9th fuel injector after the engine so far as fuel dilution goes affecting oil change mileage? I would think dilution should be much less of a concern with the current setup. I’m only at 19K on the truck currently but we have a trip to IN coming up soon and that will push my change interval to about 7700 miles post trip and I am planning to also do the fuel filters then too (approx 20,500 miles then). All of my fuel is bought at high volume truck stops. Using Motorcraft filters and Shell Rotella T6 5W-40.

 

On the newer trucks with the 9th injector, y'all can afford to stick to factory intervals. Even so, on the newer trucks, I'd recommend what you're doing. Sure, with the addition of the 9th injector it eliminates fuel dilution in the oil, but with how expensive these engines are 7500-8000 miles is plenty. I remember the heyday of the 6.4 Powerstroke and how the engine made oil; not so on the newer trucks. Keep doing what you're doing, whether it was the Geo or your V10 Excursion, you've always taken good care of your fleet

 

With the high cost of just oil and filts for the diesel. Makes sense to spend money on oil analysis. You might be able to easily go 6000 miles on oil changes. Or maybe not.