2003 Ford Explorer Sport XLT Differential Fluid

[TalNum]

Hey all,

I am seeing some conflicting information on this and was looking for some input.

I just changed out my rear differential fluid on my 2003 Ford Explorer Sport XLT (8.8 rear end).

The manual says to fill it between 5.5-5.8 pints (2.75-2.9 quarts) as well as adding a friction modifier (4oz/0.125 quarts).

My father in law told me to fill it until it was dripping out of the fill hole. I only had 3 quarts of the Motorcraft 75w-140 gear oil and the 4 oz of the friction modifier. I added all 3 quarts and the 4oz of FM but did not see it dripping out of the fill hole.

I stuck my finger in the fill hole and found the level to be pretty close. I see some people swear by the manual's amount and leave 1/4" from fluid level to fill hole while others swear by filling it entirely until it drips out.

I am kind of in a jam and can't get my hands on any gear oil this weekend and was wondering if what I filled my differential with would suffice or if I should worry? Thanks in advance, guys.

 

[JayhawkRoy]

Since you got the fill amount in the differential that your manual calls for, you are OK. I would get another bottle tomorrow and fill a bit more, but the 3 qts plus 4 oz you put in should be sufficient.

I used to use the "fill until it comes out" method, because it is easy and simple, but it could also be a bit of overfill. That said, I never had a differential have a problem due to either method.

 

[zeng]

Worry not , it should suffice.

 

[TalNum]

Originally Posted By: JayhawkRoy
Since you got the fill amount in the differential that your manual calls for, you are OK. I would get another bottle tomorrow and fill a bit more, but the 3 qts plus 4 oz you put in should be sufficient.

I used to use the "fill until it comes out" method, because it is easy and simple, but it could also be a bit of overfill. That said, I never had a differential have a problem due to either method.


Phew! Puts my mind at ease I won't be hearing grinding gears.

I will certainly top it up tomorrow just to be sure, but I am glad that if I at least filled it to manual specifications I won't fry my rear end.

 

[TalNum]

Originally Posted By: zeng
Worry not , it should suffice.

Thanks for the input and thanks for the welcome!

 

[Ethan1]

Most trucks go to the junkyard with their factory fill of gear oil, so you're gonna be OK

 

[Astro14]

On both my Explorer and Expedition, the factory service specs said something like: fill with specified amount, then check that level is within 1/4" of fill hole.

So, in my toolbox there is still a bent piece of thin steel bar stock that I used as a differential "dipstick" when I owned a couple of Fords.

You don't need to fill it until it runs out the fill hole. You're good as is. You would also be fine if you added a bit.

 

[Kira]

Were you able to clean the crumbs out of your diffy-Q?

Was there a removable back plate or just 2 plugs?
I ask because my friend's son has an '04 Explorer and I like to approach him as an "expert". Kira

 

[TalNum]

Originally Posted By: Astro14
On both my Explorer and Expedition, the factory service specs said something like: fill with specified amount, then check that level is within 1/4" of fill hole.

So, in my toolbox there is still a bent piece of thin steel bar stock that I used as a differential "dipstick" when I owned a couple of Fords.

You don't need to fill it until it runs out the fill hole. You're good as is. You would also be fine if you added a bit.


This is essentially what I had read too, which made me wonder why I see people so split on whether to fill it until it runs out or fill it to spec.

I think I will still top it up a bit when I get my quart of oil tomorrow, but it doesn't sound like a commute to work and back will hurt anything given that I have filled it to spec. I was able to stick my finger in a bit and pull out some oil.

All the same, thanks for the input. This is all putting my mind at ease that I won't be hearing the song of the grinding gears!

 

[TalNum]

Originally Posted By: Kira
Were you able to clean the crumbs out of your diffy-Q?

Was there a removable back plate or just 2 plugs?
I ask because my friend's son has an '04 Explorer and I like to approach him as an "expert". Kira


I was able to remove the back plate on the rear differential and clean out some of the sludge that had been built up over time. The difference was night and day!

I may be mistaken, but is the 2004 Explorer standard with a different type of rear end other than the 8.8 that came on the 2003? Mine is a 10 bolt, 3.73 limited slip, 8.8 rear end. No drain plug that I saw on the pan side but the filler plug is opposite to the pan side, driver side.

The factory fill plug is the standard type plug that includes the magnet which catches any metal shards that the gears produce.

 

[andyd]

Ford/Dana de-contented the diffs and the diff2 only have a fill hole. to drain you drop the cover , so you'll need a gasket. I came to the conclusion that filling till it runs out is over filling a bit. If it has an LSD, then I recommend using a lube that has the friction modifier already in it. Mobil 1 75/90 otherwise 80/90 dino.

 

[Astro14]

Originally Posted By: Kira
Were you able to clean the crumbs out of your diffy-Q?

Was there a removable back plate or just 2 plugs?
I ask because my friend's son has an '04 Explorer and I like to approach him as an "expert". Kira


I honestly don't remember....I think I had to pull the cover to drain them, unlike my Toyota that has magnetic drain plugs for both the front and rear diffs....

 

[artificialist]

Originally Posted By: andyd
Ford/Dana de-contented the diffs and the diff2 only have a fill hole. to drain you drop the cover , so you'll need a gasket. I came to the conclusion that filling till it runs out is over filling a bit. If it has an LSD, then I recommend using a lube that has the friction modifier already in it. Mobil 1 75/90 otherwise 80/90 dino.

Ford would have called for 75w140 synthetic. Ford vehicles that originally called for 80w90 were often back-speced to use 75w140 syn.

 

[01rangerxl]

Originally Posted By: Kira


Was there a removable back plate or just 2 plugs?
I ask because my friend's son has an '04 Explorer and I like to approach him as an "expert". Kira


A 2002-2010 4-door Explorer with the independent rear suspension (IRS) and 8.8 diff does have a drain plug on its finned aluminum cover, along with a fill plug that is lower than the front side one on solid axle versions.

A 2003 or older Sport has a solid rear axle and either a stamped steel or plastic cover from the factory, with no plugs on the cover. Same for 2005 and older Sport Tracs.

The IRS 8.8 takes less fluid than the solid axle versions because it doesn't have axle tubes to fill and internal axles to lubricate. I am not sure exactly how much fluid the IRS one calls for though. A lot of people swap the IRS covers on to solid axle trucks because they are cheaper than aftermarket upgrades like Mag Hytec or PML, but sometimes the mounting ears on the IRS cover need to be cut off for clearance with sway bars and such. The fill plug on the IRS cover should not be used if installed on a solid axle...it will be underfilled because of it's lower location.

The solid axle 8.8 in my Ranger takes at least 3 quarts to get to the bottom of the fill plug. As long as it has the stated capacity in it, and you aren't running an oversize cover, it's fine.