Proper 8.8 Rear Axle Fluid Level - How?
04-30-2018, 03:24 AM
#1
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Proper 8.8 Rear Axle Fluid Level - How?
Members,
I have found conflicting information about how to verify the correct fluid level in the 2016 Ford F-150 I have with the 8.8 rear axle (3.73 non-limited slip). The owners manual says 2.75 quarts (5.5 pints) while Amsoil's website states 2 quarts (4 pints) as the capacity. I can work around different reported capacities as along as I can verify if the fluid is supposed to have a light drip out of the fill plug when it is full or is it supposed to be as Amsoil's website reports as "Fluid level should be within 10 mm (0.39 in.) below fill plug opening." The owners manual says nothing but most videos and forums say to let it drip from the fill plug but others stress this is incorrect. What does Ford have to say about it in the newer generation F150s?
Thank you for your help.
I have found conflicting information about how to verify the correct fluid level in the 2016 Ford F-150 I have with the 8.8 rear axle (3.73 non-limited slip). The owners manual says 2.75 quarts (5.5 pints) while Amsoil's website states 2 quarts (4 pints) as the capacity. I can work around different reported capacities as along as I can verify if the fluid is supposed to have a light drip out of the fill plug when it is full or is it supposed to be as Amsoil's website reports as "Fluid level should be within 10 mm (0.39 in.) below fill plug opening." The owners manual says nothing but most videos and forums say to let it drip from the fill plug but others stress this is incorrect. What does Ford have to say about it in the newer generation F150s?
Thank you for your help.
04-30-2018, 05:34 AM
#2
Shop manual states "to the bottom of the fill hole" for over 35+ years I always stuck a finger in the fill hole, and if I could feel the oil, it's full.
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04-30-2018, 11:51 AM
#3
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Ford changed the spec in the late 80s or early 90s to 1/4-9/16" below the fill plug retroactively for all 8.8s back to '83, as this caption shows:
IDK how long it stayed there, but certainly through 2002 because that service manual says the same thing. It also specifies:
...in one place, and...
...in another. That's the latest manual I have on this computer right now, or I could check up to '07. After that, the manuals are only available online, and I don't have a subscription.
IDK how long it stayed there, but certainly through 2002 because that service manual says the same thing. It also specifies:
Originally Posted by 2002 F-150 Workshop Manual (Procedure revision date: 10/03/2005) SECTION 205-02A: Rear Drive Axle/Differential — Ford 8.8-Inch Ring Gear IN-VEHICLE REPAIR
Fill the rear axle with 2.54 liters (5.37 pints) of rear axle lubricant and install the filler plug.
Tighten to 30 Nm (22 lb-ft).
Tighten to 30 Nm (22 lb-ft).
Originally Posted by 2002 F-150 Workshop Manual (Procedure revision date: 08/17/2004) SECTION 205-00: Driveline System — General Information SPECIFICATIONS
Rear axle liters (pints) 2.60 (5.5) (6-14 mm [1/4-9/16 inch] below the bottom of the filler hole)
Last edited by Steve83; 04-30-2018 at 11:53 AM.
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04-30-2018, 04:01 PM
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04-30-2018, 09:40 PM
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Last edited by 2016FordF150; 05-01-2018 at 02:35 AM.
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04-30-2018, 10:03 PM
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Based on Hopey's CGIs, I'm guessing the reason the spec was changed back to fill-hole-level is because they moved the fill hole down to the oil level. On the early 8.8 casting, the fill hole is above the web on the driver's side.
(phone app link)
Now, the question becomes: what YEAR did they redesign the axle casting? Apparently, somewhere between '02 & '13.
(phone app link)
Now, the question becomes: what YEAR did they redesign the axle casting? Apparently, somewhere between '02 & '13.
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05-01-2018, 02:43 AM
#9
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Based on Hopey's CGIs, I'm guessing the reason the spec was changed back to fill-hole-level is because they moved the fill hole down to the oil level. On the early 8.8 casting, the fill hole is above the web on the driver's side.
(phone app link)
Now, the question becomes: what YEAR did they redesign the axle casting? Apparently, somewhere between '02 & '13.
(phone app link)
Now, the question becomes: what YEAR did they redesign the axle casting? Apparently, somewhere between '02 & '13.
05-01-2018, 06:50 AM
#10
No, the fill level has nothing to do with them moving the plug, my Mustang has the same level requirement but with the fill plug on the front of the drivers side. It is because they have had axles that are overfilled, get too warm and blow oil out the axle shaft seals. Ford has several solutions to this, including the “turkey baster” type expansion vent. They also have a few vent locations, one being on the axle tube, the other being on top of the diff cover. You can also get a axle cooler Assy which has a pump, lines and a front mounted radiator.
Last edited by Hopey; 05-01-2018 at 07:36 AM.