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
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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