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Amsoil Fluid Weights (Front/Rear Diff & Transfer Case)
Been back and forth trying to find a consensus (if that's possible online) for fluid weights for my 2017 F350 (m275), I read in one of the FB groups that there may be some newly approved or different recommended fluids than what is in the manual.
Truck has just under 80,000 miles on it with a few seasons of pulling our TT. I'd like to change the fluids this week or next. Info below is what I pulled from Amsoil's site. Any info or insight is greatly appreciated.
If Amsoil has a fluid recommendation their engineers have decided that that fluid complies with the OEM spec. Dont take that to mean it will be listed on the spec because Amsoil doesnt and will never pay licensing fee's to claim a spec.
If they dont know that it meets a spec, they wont list anything. There's lots of things they dont have recommendation for because they dont have something that meets the spec.
I have had discussions with them about stuff like this before. There is a fluid or 5 that people run in various things, but Amsoil says "it doesnt meet the OE spec" so they wont publish it...yet lots of people run it in a non recommended way.
Just one example is that Amsoil will never recommend a racing oil or a high zinc oil for anything, but that doesnt mean its wrong to run it, just that "you better know what you are doing".
The fluids listed above are what I would recommend for your truck and what I plan to put in my truck at some point in the near future.
IIRC OEM on the front end was a conventional 80w-90, you can run a 75w-90 or a 80w-90 without issue, the M275s are 75w140 from the factory so I would stick with that weight, the sterlings got the odd ball 75w85. I ended up throwing a 75w140 in mine. The transfer case is Mercon LV, I think the amsoil like provided is the amsoil equivalent so that should be fine. In an x-case you are probably fine with even generic mercon but I threw in the left over LV I had from when I dropped the pan on my 6R140.
Ok, crawled under the truck and started to doubt myself. Is this the m275 rear diff? I thought there was a drain plug but after a closer look, I don't think there is....that ks for the help all, first time changing rear diff fluid for me.
Not sure on that, just changed today. Haven't driven it yet. Had kid stuff for the rest of the day, so I'll get the front diff and t-case tomorrow morning.
Not sure on that, just changed today. Haven't driven it yet. Had kid stuff for the rest of the day, so I'll get the front diff and t-case tomorrow morning.
Do people notice a difference in mileage?
It's possible. There is a fuel economy difference between running 80w90 and 75w140. Maybe you gain some power to the wheels and fuel economy from switching out 80k mile Motorcraft fluid to Amsoil full syn?
I've been able to get the rear diff and transfer case done, both pretty easy. Does anyone know if the lower right bolt on the front diff is also a drain plug like the rear? I'd like to drain first and then pop cover off to reseal.
Truck isn't my daily driver, so haven't driven any real distance until this past weekend. Maybe a little better fuel mileage...I don't normally watch fuel mileage but it didn't seem to go thru it quite as fast...very scientific I know.
It does seem to shift a bit smoother, but maybe that's just because I'm trying to feel for it...
Now I'm onto the transmission fluid and front diff. Anyone know if I can drain the front diff the same way? Lower right bolt as a drain plug?
If Amsoil has a fluid recommendation their engineers have decided that that fluid complies with the OEM spec. Dont take that to mean it will be listed on the spec because Amsoil doesnt and will never pay licensing fee's to claim a spec.
If they dont know that it meets a spec, they wont list anything. There's lots of things they dont have recommendation for because they dont have something that meets the spec.
I have had discussions with them about stuff like this before. There is a fluid or 5 that people run in various things, but Amsoil says "it doesnt meet the OE spec" so they wont publish it...yet lots of people run it in a non recommended way.
Amsoil is kinda like Amway, a pyramid scheme, where every Tom, Dick and Harry tries to pawn the stuff. That and some of their products don't have API certification (or at least didn't last time I checked)
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