All fluids changed @ 70K miles

[happyfer22]

https://www.amsoil.com/p/amsoil-severe-gear-75w-85-100-synthetic-gear-lube-svl/?code=SVLPK-EA

Sponsored

 

[710-oil-614]

Just to clarify — the PTU doesn’t have a filter like a transmission, and it runs hot under load. Heat + no filtration = faster fluid breakdown. Mine came from the factory with less fluid than spec, and what came out at 5K miles looked bad.

I get that some folks trust the 36K warranty — I prefer to trust preventive care. Swapping fluid every 20K is cheap insurance for a part I expect to last 200K miles. $20/qt of AMSOIL and 15 minutes well spent. Drain & Fill .

Not trying to scare anyone — just sharing what I’ve seen. Drive safe.

What amsoil fluid did you switch to? I used motorcraft but would definitely swap to Amsoil. I know @Snox801 runs Amsoil....

 

[happyfer22]

What amsoil fluid did you switch to? I used motorcraft but would definitely swap to Amsoil. I know @Snox801 runs Amsoil....

https://www.amsoil.com/p/amsoil-severe-gear-75w-85-100-synthetic-gear-lube-svl/?code=SVLPK-EA

 

[710-oil-614]

https://www.amsoil.com/p/amsoil-severe-gear-75w-85-100-synthetic-gear-lube-svl/?code=SVLPK-EA

What about for RDU?

Definitely feel like I'll be changing again at 10K oil change LOL.

 

[thev8man]

Just to clarify — the PTU doesn’t have a filter like a transmission, and it runs hot under load. Heat + no filtration = faster fluid breakdown. Mine came from the factory with less fluid than spec, and what came out at 5K miles looked bad.

I get that some folks trust the 36K warranty — I prefer to trust preventive care. Swapping fluid every 20K is cheap insurance for a part I expect to last 200K miles. $20/qt of AMSOIL and 15 minutes well spent. Drain & Fill .

Not trying to scare anyone — just sharing what I’ve seen. Drive safe.

Booyah
While I'm at 17700, and I've been wildin' so probably in need of an insurance policy adjustment. It's was only one quart?

 

[Timothyd]

Hit 70k so swapped my oil to 5w50 amsoil because I’m doing some heavy hauling in the heat the next few months. Trans fluid with amsoil not the ultra low viscosity. And ptu fluid. Also drain flushed and filled with engine ice for coolant.

All fluids looked good going out. Did rdu a few weeks back.

The normal stuff on the magnets and fluids looked very very good even after all the abuse I’ve put them through. I swapped everything early to amsoil and redline.

Break fluid?

 

[OffGrayMulchWagon]

Does Ford monitor this forum? Has anyone contacted FMC about reported drivetrain fluid issues?

Is FMC using too little fluid, bad fluid or both?

 

[mavhopefull]

Hit 70k so swapped my oil to 5w50 amsoil because I’m doing some heavy hauling in the heat the next few months. Trans fluid with amsoil not the ultra low viscosity. And ptu fluid. Also drain flushed and filled with engine ice for coolant.

All fluids looked good going out. Did rdu a few weeks back.

The normal stuff on the magnets and fluids looked very very good even after all the abuse I’ve put them through. I swapped everything early to amsoil and redline.

So we can use other non ulv transmissions fluids? And using non ULV would improve longevity of the transmission? I'm interested also as I do quite a bit of towing with mine. At 30k the Transmission Fluid was dark and horrible.

 

[happyfer22]

Yeah, great question — and I’ve been digging into this a lot too.

Best advice? Always double-check with the fluid manufacturer. I called AMSOIL’s tech line myself — they’re super helpful and can confirm exactly what works for your truck.

That said, AMSOIL’s ATF (both the Signature Series and Fuel-Efficient versions) are 100% synthetic with a PAO base — way more resistant to heat, breakdown, and wear compared to the factory ULV stuff. Honestly, it’s night and day.

 

[Cherokee]

No doubt about it Amsoil is a good product line, like Mobil 1 and Pennzoil.

145,000 miles on my 2010 Mustang,
167,000 on my 2013 F-150,
350,000 on my 1998 Ranger
137,000 on my 2016 Transit Connect 2.5L 4 banger, This was the Ranger engine of old just
slightly enlarged to 2.5L
Transmission, differentials, RDU PTO's Engines all on FoMoCo products.
All on Motorcraft fluids, all with ZERO Issues, all sold still running great.

I have not once seen any data that the factory fluids are not just as good and protect just as well.
Same as In my Harley days, I used the MoCo products, had several friends
who lived and breathed Amsoil. They had no problems and they kept telling me I needed to switch.
I never did but like them I never had problems.
I ran the crap out of my 2008 1200 Roadster, Rode it like a sport bike. My factory HD oil never let me down.

Just expressing my opinion from all my decades of my engine experience.

I took a Taco 2.7 ltr 4 banger to 528,000 miles, all severe duty.
On Mobil 1 full syn at 10,000 mile change intervals. All of the engines listed above, all 10k oil intervals.
I wore the Taco out, literally as the compression was falling, Ya think !
I drove all but the Mustang about 80-90,000 miles a year In the Central Florida heat.
with heavy loads and pulling small enclosed trailers.

I'd say I got it right.

 

[happyfer22]

Totally appreciate your experience — and honestly, that's impressive mileage across all those vehicles. No doubt Motorcraft fluids have done the job well for you, especially under NC heat and heavy loads.

In my case — over 1 million miles in the last 15 years between fleet and personal cars/trucks — I’m just wired for preventive overkill. I’ve had great results using AMSOIL for 20+ years. Not saying Motorcraft is bad at all (clearly it works!), but those are mostly Group II & III oils. Personally, I like the peace of mind that comes with running PAO-based 100% synthetics in the PTU, RDU, and transmission — especially for components like the PTU or transfer case and front/rear diffs that don’t have filters and run extremely hot.

AMSOIL saves me money long-term thanks to extended drain intervals — but that’s another story.

So yeah, nothing wrong with sticking to factory specs — I just lean a bit more obsessive on the maintenance side, and that’s what works for me.

All respect, and thanks for sharing your history — 528K on a Taco is seriously impressive

Best ,

 

[MaverickNoticer]

Are there any issues with using the heavier oil?
How did you decide on that weight?

 

[Snox801]

Are there any issues with using the heavier oil?
How did you decide on that weight?

Zero issues, trans shift great and it clearly holds up better to heat than the factory stuff.
As for weight on engine oil. All ford performance stuff says to run 5w50 for track use. So it clearly won’t hurt it. I also have the same oil pressure upon start up. And seemed to keep standard pressure when hot.
I went through. The mountains in 98 degree weather yesterday for 12 hours. Highway speed 72mph saw temps climb to about 220 then drop right back down to 185. Trans stayed right at 185-200.
Engine ice definitely dropped the temp back down faster once the t stat opened. Than with factory fluid. So far I’m happy.

 

[The Real Maverick]

What blinker fluid did you use?

 

[Snox801]

Valvoline

Sponsored