My Expedition has about 35,000 miles. I want to change the rear end fluid. It's got (I think) the 9.75" rear end, with LS. Do I use 75W140, or do I use 75W90 (which I understand also goes in the front)? I have some extra Amsoil 75W140, which I'm planning to use, but I don't want to screw anything up. I can't tell the oil weight from the owners manual.

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97 Expedition XLT 4x4, Black, 3.73 LS, 5.4L, leather, all options except LLS, Edelbrock IAS shocks

 

My truck has a metal tag attached to the "pumpkin" that says the weight and that it uses synthetic.

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1999 F250LD Lariat s/c
Deep Wedgewood/Harvest Gold
Class III Tow pkg.
255/70/16 tires
5.4 v8
3.73LS rearend
Auto trans.
16,000 mi.

 

Go to www.ownerconnection.com and download the owner's manual. You have to "join" their site, but it's a good place to get electronic copies of info for your X.

The gear oil to use is a synthetic 75W140. You'll also need a "friction modifier" for the LS.


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1997 4x4 Expedition- 4.6L, true dual exhaust w/glass-packs, K&N air filter, SuperChip, airbox mods, Edelbrock shocks, 285/75R16 BFG ATs, 2000 "XLT" wheels, 4.10 gears, Auburn LS, Clarion In-dash CD player, Smitty Bilt push bars and nerf bars.

2000 4x2 F150 XLT Reg. Cab LWB- 5.4L, Tow Pkg, 3.55LS, CD player,Remote Keyless Entry, Sliding back glass, Special Appearance Pkg., tinted windows, Line-X bedliner, K&N air filter, SuperChip, airbox mods, 285/60R16 Goodyear Eagle GT IIs and Prime #155 wheels.

http://members.visualcities.com/NoMo

 

If you are looking for the best synthetic oil 75w-140 I have only found one that stands above the others. It is from Lubrication Engineers and it's called LE 9920. You can call Mag-Hytec and get the information from the owner (Roy) at 1-818-786-8325. Make sure he tells you about the tests that have been done for him.

Sincerely, Kevin

 

Thanks to all for the info.

I think that the Amsoil alsready has the friction modifier for the LS in it.

Oil Man: I've already spoken to Roy and Mag-Hytek. I also have an F-350, and I got a diff cover from them. If I didn't already have the Amsoil, I would get the LE. Maybe next time.

Thanks again to all.

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97 Expedition XLT 4x4, Black, 3.73 LS, 5.4L, leather, all options except LLS, Edelbrock IAS shocks

 

1. I think the 4.6 comes with the smaller rear?

2. The ONLY reason to change the grease at 35K is if you tow or you've submerged it in water.

Those are SEALED rear's that come with synthetic lube and are supposed to go 100K.... Although I would change it at 50K....

I changed both front and rear. I have the larger rear and it uses synthetic 75W140 and the front uses 75W90. I used Amsoil in the rear and Mobil1 in the front.

Dont forget about the TRANSFER case. You should change that at 24K or 2 years. Use synthetic ATF.



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Rand

98 Ford Expedition 4X4 XLT
5.4, 3.73s, 17" wheels,
Homemade 3" "COLD" Air-Box
mod, SuperChip, Amsoil
everywhere but tranny, Perma-
Cool combo 6 pass trans/oil
cooler (FQR 5.4 @ 50K)

 

Jon P,
The 9.75" has a 12 bolt cover. The 8.8" has a 10 bolt cover. If it is the 9.75" LS, you more than likely will need the 75/140. Stay with a synthetic. Personally, I use the Ford lube. However, Only recently can I take temp readings. From what I;ve read, if the diff gets over 200F, I'll probalby change to the "LE" that ROy @ Mag Hytec sells. I've heard great things about it.

Regarding the life of the original oil, I would draw an oil sample and send to www.blackstone-labs.com . E-mail them first, they will send a free sample kit.
I changed mine at 40K, only because I do a moderate amount of towing (2.5klb-7klb, 8-10x/yr., 10mi-600mi). Their analysis showed the following: (metal reading/Avg.) Iron 511PPM/396PPM, Nickel 17/2, Manganese 15/8, Boron 136/117, Silicon 46/70, Sodium 26/18, Calcium 15/526, Phosphorous 2176/1126. Their comments (paraphrased), "After 40K miles, this diff lube is definately due for a change because of accumulated abrasion in the oil. The Iron and Nickel are steel alloys from the same steel parts, probably gear teeth. Silicon may be abrasive dirt. No moisture found. ...Insolubles show the oil is oxidized... Wear accumulations are probably normal."
If you only draw a sample, be sure to refill the diff to proper level!
Originally, I had "Jiffy Lube" suction the fluid out. Not only did they not suction ALL the fluid (~1/2pt remained) they did not tighten the fill plug. I'll never be back!
If you are somewhat mechanically inclined, take the ~2hrs to pull the cover, drain the fluid (take a sample) and replace the cover and fluid. Don't forget the Friction Modifier! The covers use silicone instead of a gasket.
If you are interested in tempeature, there is some room at the top of the cover, opposite the ring gear, to install an Autometer temp sender (1/8" NPT). You can switch between 2 sensors and one gauge. THat's what I did! Trans and Diff Temp.

Once I wire it in (Today) I'll post some results.

Let us know waht you decide.

Tony

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97 F150, 5.4l, E4OD, Towing Package, and every option except leather seats

 

I'm quite skeptical of the "sealed for life" claim. The rear end on Super Duties is supposedly also "sealed for life," yet lot's of people on the Ford-Diesel site have found their fluid shot after 30,000. F150Tony's results would seem to bear this out. Several people on the F-D board have also posted that their diffs were underfilled from the factory. I don't think that it would hurt to change it at 35,000. I'll probably change the front diff to Mobil 1, which is easy to find locally, at the same time.

I changed the transmission and transfer case to Mobil 1 ATF at 20,000.

 

Jon P,
I can't stress it enough... If you can, pull the cover yourself, and take an oil sample. Afterall, you only nee a 13mm or 1/2" socket, torquewrench, and silicone. You'll be able to physically inspect the gears, and the oil analysis will give you insight into how things are wearing.

Let us know how things go.

Tony

 

I changed the rear-end fluid on my Super-duty this weekend. I also installed a Mag-Hytec cover, which I recommend HIGHLY for you 150/250 owners. Unfortunately, the track bar on the Expedition means that no one makes an after-market high capacity cover, since the stock cover is a tight fit as it is.

20,000 miles on the Super Duty, and the fluid was black/grey soup. Smelled vile, but I think that's the friction modifier. I replaced it with 6 quarts of Amsoil 75W140, which has the modifier in it.

I didn't take an oil sample, since it only had 20,000 miles, but I may take a sample the next time around, The Mag-Hytec cover has a dipstick with a magnet. After about 50 miles, the fluid is quite clear, but I picked up a small amount of fine shavings (which I think were in the little bit of old fluid that remained.) The gears looked fine.

I'll probably take a sample from the Expedition when I change the fluid this weekend. I'm planning on changing the front to Mobil 1 75W90 at the same time.

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97 Expedition XLT 4x4, Black, 3.73 LS, 5.4L, leather, all options except LLS, Edelbrock IAS shocks

 

I would like to pull the rear dif cover off, change to AmsOil and get the sample done. I have a few questions?

1) How do I reseal the dif cover if it is permanent? Is there an aftermarket gasket?

2) What is the proper torque setting? Where would I find this information?

Truck is a 2001 Screw, 4x4, AT.

Any help appreciated!!!

[This message has been edited by digodell (edited 09-18-2000).]

 

digodell

It's not permanently sealed. There is no gasket, just use black RTV sealant. I've got the Helms manual at home (I'm on the road), and I'll see if it has the torque specs.

The Mag-Hytex cover is torqued to 16ft-lbs, but it uses a rubber O-ring seal and no sealant, so it might not need as much torque as the stock cover.

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97 Expedition XLT 4x4, Black, 3.73 LS, 5.4L, leather, all options except LLS, Edelbrock IAS shocks

 

Why bother doing an oil analysis if your going to pull the cover, change the freaking oil! Why go through the time and expense if you have fresh oil?

Does not make sense to me. If you want a sample, take a straw or tube and place it in the fill-hole. Once its got some fluid in it, hold your finger over the end of the tube and VIOLA! That way you can do the test and get the RESULTS before you change the fluid!

Putting the CART BEFORE THE HORSE?

 

Rand,
There are several points to oil analysis:

1) Status of the Gears & Friction plates (in an LS) that physical inspection will not reveal (alloy particle counts). You may be able to head off a gear failure by changing the oil more frequently, or rebuild the gear set before it fails & leaves you stranded.

2) How the oil is aging. This will help determine frequency of the oil change.

3) High temp oxidation to the oil. Again, these results would point to oil change frequency.

4) FORD states the gear oil never needs changing. My oil analysis proved otherwise. Actually it should have been changed much earlier. Look earlier in this post for my results.

Botom line: Yeah, you probably could guess at the oil age/life in your diff, and it may last just fine, but why take the chance. $20 for the analysis and $60 for the oil change (FORD 75W140+FM) and 2 hrs every 10K or 20K miles is a lot cheaper than having the diff fail towing a load across the high desert in the summer, with your family along!

Try it: www.blackstone-labs.com

BTW, I am not affiliated with Blackstone Labs, just a satisfied customer.

Take better care of your vehicle and it will take better care of you.

Tony

 

i've got the 4.6 4x2-150 with the limited slip rear..iwould like to change it out to synth what weight and brand do you guys reccommend?