2018 f150, amsoil into 10r80 trans and rear differential, 29000 miles

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5,011
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Bottom line, I‘m glad I did it.

First, I don’t think there was anything wrong with the truck when I started. I’m an easy driver, as told by the ~20mpg average fuel economy reading, and that includes long idling if I get stuck on the phone in the nasty heat. Second, I tend to ”run quiet.” It has modest ATs on it (Continentals), 18” wheels, and if the radio is on, it’s mostly spoken word. It does see towing - 2-3 times a year out of state with a travel trailer. We like hilly places for camping. Truck gets 10-30 synthetic every 7500 miles.

That said, 2 things have been creeping up. Starting last November, it started the mildest of differential whine, most noticeable at 50mph before wind noise takes over. At such a low mileage, I wasn’t keen on immediately jumping to a fluid change, however after 3 interstate trips recently I started re-thinking this. The second - this truck never ever gives a sloppy shift under power, but it can be very clumsy at light throttle, mostly where I tend to drive. This spring/summer has had a marked increase in light-throttle shift clumsiness.

I vacuumed out about 1.75 quarts from the back axle. It looked like motor oil at 5,000 miles. That is, it was black, even as seen through the middle size mityvac hose. And though cold, the mityvac had no issue pulling it out. Did I mention it was black? I’ve never seen diff oil come out like this. About 2.25 quarts of severe gear 75-90 went in. This is an open diff with e-locker.

For the trans, goodness the fill plug was tight. An open-ended wrench wasn’t strong enough and the angles are limited for a 19mm closed-end wrench. I couldn’t get it to budge by hand, and got it loose by kicking it. 4 quarts came out, and an additional 1.75 after letting it idle for 30 seconds. I checked it before draining to make sure the level was right. This fluid Is the new Merton ULV standard I believe. It looked like 30,000 mile fluid should; a little red as it dripped, though more of a brown in the mityvac lines that would not show much light through it. A smidge more than 5.75 quarts of Amsoil’s low-vis signature series ATF went in, as recommended by their site. Note- the old fluid was very thin, almost like brake fluid. Amsoil is a bit thicker. The Ford forums have a very mixed opinion on moving away from exact ULV for the 10r80 for this reason.

Result. After driving a bit, I’m glad I did it. On hills I drive regularly, it’s holding one gear higher. The cab is notably quieter - I had no idea - can’t tell if it changed the front or the rear or both, but it’s like someone threw a blanket over it. After a few minutes of driving, the shifting clumsiness stopped. I still notice when it shifts, but it doesn’t feel awkward. It just shifts and moves on with its life.

This is my first ford - Ive no experience with them, and its probably the vehicle I’ve enjoyed more than any other. IDK if it’s normal, and by all means it’s an early service, but I’m glad I did it. Oh - there was very little fuzz on the diff fill bolt magnet (I didn’t pull the lid, just evac’ed the fluid).

-m
 
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Messages
4,630
Location
Decatur AL USA
You did the research. You made the decision. I'm not about to criticize

I would have been hesitant with drivetrain warranty remaining and possible issues.

I hope it works out well. Let us know ongoing how the it the Amsoil performs in this application.

Do check the shop manual for the rear axle fluid level. I'm thinking I read the diff isn't supposed to be filled all the way to the hole now. I believe that's on the 9.75" but I could be incorrect.

I do know the trans isn't supposed to be filled to where the stick indicates. They lowered the fill level after intro because when they heat up the fluid overflows the vent. It's not supposed to be to the top of the cross hatch.
 

meep

Thread starter
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@Gene. You are indeed wise. I made the decision carefully. What you said regarding the level check, let me run this by you - mine has 3 sets of hash marks. A cold set below 90F, a middle set which is maintenance temp, and a higher set which I never saw defined. Mine was in the middle of the lowest set, cold (spot on per the pdf I found on the internet, so it must be true!) Is that the revised design you speak of? I’m assuming that a small portion of my fill remained in the 6ft of tubing and bottles, the amount in should be extremely close to what came out. I hear you regarding the diff. I’ll go look it up - old school me always did to the bottom of the fill hole.

@spasm3. At load, air would be a bad thing. But under no load, plenty wet, idle speed, ive never had an issue with it. What happens is it pumps air into the TC and then atf with small air bubbles comes out, and then it levels off as a fluid/air mix; and I get a more complete fluid replacement. I usually do this the first big change and then “stay by the book” after that. It’s never really dry. The biggest thing I’ve learned to watch for is it can complicate getting the final level right; you’ve got to run it and let it settle a bit after refilling to let the air work out before getting a final level check. BUT, ymmv- I certainly wouldn’t recommend it as a rule for anyone else to follow, it’s just a personal level of comfort.

Ill let you know how it goes. We drove it tonight and even my wife noted the difference in sound level.
 
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23
Location
TX
How is the transmission acting with the amsoil fluid? Did yours have the 3-4/3-5 stumble when cold? I have a 19 F150 and want to use amsoil in the transmission when I change the fluid at 30k.
 

meep

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Mine has the stumbles both hot and cold, yes. So the amsoil smooths it out some but it’s still there. It still seems to be improving, slowly, so for now I’m going to leave it as is. Frankly I’m not yet sold on it. The overall shift grabs quicker but completes just a hair slower, if I’m being totally @nal retentive, which makes sense as a slightly thicker fluid. Overall the effect is that it doesnt slap into gear at the end of the shift, which is a nice improvement. If I could do it again, I would have swapped 2 quarts, maybe 3, for the additive package and slight boost in viscosity and tried that ratio. I might actually swap 1-2 quarts of Mercon ULV back in just to back the viscosity down a touch. But, first, I’m going to just drive it.

there is a pdf on the web where one really enterprising dealer worked on one of these 3 times and eventually swapped out the valve body, fixing it. I can’t see mine doing that for free under what‘s left of the warranty, and don’t really want them to. So it makes me wonder if there’s a flaw in how the valve body wears in. Being that mine does seem to be improving a touch, slowly, I’ll give it some time.

that, and idk if it was the transmission or the rear axle, but doing both has resulted in a quieter ride and holding a higher gear better going up hills. the axle definitely needed it, based on jet black fluid.

as far as a full change to amsoil, as much as I’m a fan of their fluids, this one is too thick for a full dose of it. I assumed before putting it in that it truly was an accurate replacement, but after seeing the viscosity difference have been a little disappointed in them, for the first time. I would not recommend a full change to it, at least not yet. Maybe they’ll come out with a ULV version.

m
 
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23
Location
TX
I see you only drained out what you could through the fill hole and with a total capacity of 13-14 quarts I wouldn't think you changed the viscosity a whole lot. ULV is 4.5 cSt and Amsoil's is 6.0 cSt @ 100c and with you changing out a little less than half of the fluid that may put you in the 5.0-5.2 cSt. With ford claiming 150,000 service life on the ulv whats not to say that the viscosity won't change that much during that period.

I do plan to drop the pan and change the filter when I do mine. Of course this will be more of a chore with the new trans cooler design but that is what shop manuals are for. Just a thought, with the adaptive shift strategies these transmissions have, maybe yours could use a reset and relearn to take into account for the small viscosity change.
 

meep

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5,011
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Southeast
Yeah, I thought that it could be adapting... as you said it’s not a big difference. I will say this... sometimes it would take 5 seconds to engage reverse.... this has not shown up since then. I paid attention today when I drove it... it’s definitely improved, though it still Had one plain clumsy shift somewhere around late engagement going into 4, but 1-3 drives more like it did new now. I haven’t found a repeatable pattern where it messes up, but it doesn’t seem to have any issues if I’m getting on it; most of its clumsiness is had with my typical “old man” driving. It’s a truck, I don’t usually get it in a hurry. I’ll be towing with it in a month, out of state. Will be interesting to see if there’s any difference there - it is programmed amazingly well for towing - marvelous programming and every experience pulling with it has been top notch; it’s nicely dialed in, never misses a shift with the load back there.
m
 
Messages
23
Location
TX
I'm glad to see your experience is mostly positive with the 10R80. This is my second one, other a 18 Mustang GT, and overall I'm happy with it. I am tuned by 5 star, mainly for the transmission tuning and it has helped from the factory tuning but still not perfect.
 

meep

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5,011
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Southeast
Update.

ive given it some time to let the transmission to adapt to the new fluid, which with the 6 qts of amsoil in a 13 quart transmission did thicken it a little. it’s still not great, and any upshift from 3rd was awkward, whether to 4th or 5th. Mail-ordered 4 qts of valvoline ULV and swapped that in today. Only drove it for a couple of miles, but this should have been the first move. It’s the best it’s been in a while, to the extent that you wouldn’t think anything was wrong - it went in and out of 3rd every time without drama. I wish I’d known that the fluid recommended by amsoil wasn’t really right for the truck but am glad to see an improvement.

ford doesn’t have a fix, dealers are just telling folks it’s normal. There’s a class action lawsuit being discussed, though a mustang forum saw this fixed by an enterprising dealer which did a valve body replacement. I wonder if there is a small part problem like a sticking accumulator piston or o-ring, because frankly, fluid shouldn’t make much of a difference here. I’m hoping to basically bide time until they actually put out a meaningful TSB, extended warranty or recall on the thing.

ill report back, this is a little encouraging, and a little fun.

happy Saturday,
-meep
 
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meep

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Update:

as a bitog purist i feel a little ashamed to admit this, but i caved and used an additive. Im not a fan of additives. BUT...

the f150 remained a bit better following the dealer reset the trans additives, but it still continued to have that lag and stumble/thunk getting up from 3rd. i remain suspicious of something not playing right in the VB.

this morning i poured just under 1/4 of a bottle (10 oz in the bottle, i was aiming for a 2 oz pour) of lubeguard red into the transmission. LG wants one ounce per quart. its a 12 qt transmission, so this is basically a 1/5 dose....

i took it for a drive and over 10-15 minutes it changed. By the end of 15 minutes i could not tell which gear it was shifting in and out of... the obvious nature of the upshift out of 3rd was not perceivable.

i dont like additives, but at least on day 1, this made a very good and significant difference.
 
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pa
OE fluids are generally semi-syn to keep costs down $$ i like real synthetics + redline is my first choice. after doing all drivetrain fluids in my 2011 frontier SV 6 spd manual with redline i netted 3 MPGS. like most nissan uses a semi syn + even with only about 30 on it being 8 YO lubes i figured it was due. manufacturers push what they sell + years ago i put Amsoil recommended Series 2000 in my 2001 Jetta 5 spd + it shifted progressively WORSE until i dumped it for redline MT 90 that shifter better + continued to get even better than NEW!!! the VAG o2j was said to have poor soft syncros!!
 
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1,728
Location
Athens, GA
Update:

as a bitog purist i feel a little ashamed to admit this, but i caved and used an additive. Im not a fan of additives. BUT...

the f150 remained a bit better following the dealer reset the trans additives, but it still continued to have that lag and stumble/thunk getting up from 3rd. i remain suspicious of something not playing right in the VB.

this morning i poured just under 1/4 of a bottle (10 oz in the bottle, i was aiming for a 2 oz pour) of lubeguard red into the transmission. LG wants one ounce per quart. its a 12 qt transmission, so this is basically a 1/5 dose....

i took it for a drive and over 10-15 minutes it changed. By the end of 15 minutes i could not tell which gear it was shifting in and out of... the obvious nature of the upshift out of 3rd was not perceivable.

i dont like additives, but at least on day 1, this made a very good and significant difference.


Interesting. I've got a bottle of platinum sitting at home and some red, I might try one or the other. The shifting on my 10R80 has been 'meh' for me. I understand the reason for the programming Ford chose (Fuel economy) but there are times when the thing just can't make up its mind, or bogs the engine down when it should have shifted. The 3/4/5 shift area does leave something to be desired as well, not sure what clutch/brake gymnastics are going on in there, but it must be some of the more difficult swapping the box does. If you stomp on it from a stop, it shifts right up through them like a champ, but farting around driving like a human the box seems to need a different brain.
 
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2,393
Location
Paradise of Florida
Change the filter

Dealer reset adaptive values and you used Lubegard red... Sounds like a win win situation. Not sure if I'd use an LV fluid in place of an ULV fluid.

 
Messages
1,728
Location
Athens, GA
the f150 remained a bit better following the dealer reset the trans additives, but it still continued to have that lag and stumble/thunk getting up from 3rd. i remain suspicious of something not playing right in the VB.
I am curious as to the programming around 3rd gear. I think I told you this in a PM, but it would be interesting to hear from other 10R80 owners.

Mine does this thing where it will do the 2-3 shift and then a few moments later feel like it is locking up the converter. Feels just like another shift, but the dash still reports it to be in 3rd. Then it will go on shifting up like normal. Its always done it, so I don't pay it much attention and I'm only 2000 miles into the truck and I have a lifetime powertrain warranty so I'm not concerned about it.
 

meep

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5,011
Location
Southeast
Drove it again today. Its a new truck, basically.

ive used full doses of LG before and didnt like how the friction modifiers might fix one problem while de-optimizing something else in the shift. With under 1/4 bottle, i dont perceive any change in shift quality in the wrong direction. Rather, there is no delay, clumsiness, flare, or flare-bang, upshifting from 3rd now. It simply goes in and goes on. Its hard to believe that 2oz of this stuff totally nailed a problem the factory is ignoring to the wall.

m
 
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1,728
Location
Athens, GA
@meep and I have been talking behind the scenes about our 10R80's. He'd done a few oz of LG Red and it made his a bit better. Mine had been much the same, the 3-4-5 sets of shifts are always pretty variable in how they engaged. Sometimes they're ok, sometimes they clunk around. Our running theory is that the solenoids and clutches are doing some form of magical dance and sometime things just don't go smoothly. I ended up putting 8oz of LG Platinum in mine a few weeks ago just as an experiment. I purposely waited for a while before reporting on it. Since I just finished a 350 mile drive, I thought I would report back.

So far, I like the change. The LG has eliminated the chunkiness in the 3-4-5 area, and doesn't really seem to effect anything else. Shifts under full throttle are still good and firm, and just tooling around they feel like they always have. One thing I didn't do that he did was reset the adaptives, I just added and rolled with it.

So far I do like it and will be doing 1oz/qt going forward when I start some D&F's here in another 15k.

YMMV
 
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