99 Mountaineer V8 front diff oil

[Hunter66]

I looked in my Haynes Manual I swear I dont see what oil to used in the front Diff
I see Transfer case is ATF
rear is Syn 75w-140

What gives??

 

[IZwack]

Go with the same!

 

[MountaineerGreen]

75w90 regular or synthetic is just fine.

 

[Hunter66]

Thanks

 

[gijoecam]

Page 234 in your owner's manual calls for 1.8 quarts of 80W90.

-Joe

 

[Hunter66]

Well I put Mobil 1 75w 90 synth. in the front, amazing how ez with the hose trick to fill. I pumped it out with the red multi purpose pump Wally world sells for 7 or 8 bux

I hope the rear and tranfer case is as EZ. tackle that next sat.

 

[Fifty150]

1997 Mercury Mountaineer

Transmission:Automatic
Fuel:Gasoline
Cylinders:8
Drivetrain:AWD
Driving Condition:Severe



o
o
o
o
o transmission - Automatic 4R70W (2WD and AWD) | 13.2L (13.9 qts) | manual calls for Motorcraft MERCON ATF, Ford part # XT-2-QDX, Ford Specification Mercon.

• [DC] RP MaxATF (part #01320)
• Lucas Semi-Synthetic AT Fluid [LOP-10052]

o tranfer case - Borg Warner AWD transfer case | 1.25L (2.64 pts) 1.3212 qts | manual calls for Motorcraft MERCON ATF, Ford part # XT-2-QDX, Ford Specification Mercon.

• [DC] RP Synchromax (part # 01512) 1st Choice, alternative - RP MaxATF (part#01320)
• Lucas Semi-Synthetic AT Fluid [LOP-10052]

o front differential - Dana 35 front axle | 1.7L (3.5 pts) 1.7969 qts | manual calls for 4X4 Gear Oil, Ford part # FITZ-19580-A, Ford Specification WSL-M2C191-A.

• [DC] RP MaxGear 75W90 (part #01300)
• Lucas 75/90 Synthetic Gear Oil [LOP-10047S]

o rear differential - Ford Traction Lok 8.8 | 2.6L (5.5 pts) 2.7482 | manual calls for Motorcraft 75W140 Premium Synthetic Rear Axle Lubricant, Ford part # XY-80W90-QL, Ford Specification WSP-M2C197-A.

• [DC] RP MaxGear 75W140 (part #01301)
• Lucas 75/140 Synthetic Gear Oil [LOP-10121S]

 

[gijoecam]

1997 Mercury Mountaineer

o front differential - Dana 35 front axle | 1.7L (3.5 pts) 1.7969 qts | manual calls for 4X4 Gear Oil, Ford part # FITZ-19580-A, Ford Specification WSL-M2C191-A.

<B>

• [DC] RP MaxGear 75W90 (part #01300)
• Lucas 75/90 Synthetic Gear Oil [LOP-10047S]

</B>
snip...

Not sure what your source was, but mine was the owner's manual for his truck... 75-versus 80-W-90 is not a significant difference.

-Joe

 

[96eb96]

My ford dealer told me to put 75W-140 in my front, because the 95-96 have the front axle disconnect. 97+ can use 80W-90. They said if I use 80W-90 there could be issues with that device in cold weather.

The owners manual calls for "motorcraft 4X4 gear oil" p/n F1TZ-19580-A.

This crosses to synthetic 75W-140.

 

[gijoecam]

Actually, 95, 96, and 97 all call for the same part number you mentioned.

Starting in 98, they specify, "Motorcraft SAE 80W90 Axle Lubricant' but don't cite a specific Ford part number or spec.

For '99, they call out 'Motorcraft SAE 80W90 Rear Axle Lubricant' which was likely the same as 98.

For '00-'02, they call out 'Motorcraft SAE 80W90 Premium Rear Axle Lubricant'. The label probably just got bigger.

Ran out of time to check later years... maybe tomorrow...

-Joe

 

[96eb96]

Actually, 95, 96, and 97 all call for the same part number you mentioned.

Starting in 98, they specify, "Motorcraft SAE 80W90 Axle Lubricant' but don't cite a specific Ford part number or spec.

For '99, they call out 'Motorcraft SAE 80W90 Rear Axle Lubricant' which was likely the same as 98.

For '00-'02, they call out 'Motorcraft SAE 80W90 Premium Rear Axle Lubricant'. The label probably just got bigger.

Ran out of time to check later years... maybe tomorrow...

-Joe

My dealer (I talk to a master tech there, not the lady at the cash register) actually told me to avoid 75W140(for the rear axle) even though it may be suggested. He only uses a good quality dino 80W90 in his truck, changed every 50K miles. Why? In the past few years Ford had lots of differential failures. There are examples on this board with photos of scored bearings after 60K miles. Does this have anything to do with 75W140? Maybe. He said that fluid is hygroscpic and absorbs water. He saw many rear ends in and out of warranty with abnormal bearing damage or rust. This was rare in the past. He said the new oil is to gain .2 Mpg(mabye) and get brownie points with Govt fuel economy ratings. I was a bit doubtful until I searched google on moisture in 75W140. There is some info on that.

This is true, I bought 12yr old used 80s crown vics that had 300K on the original diff with regular 80W90 changes. The gears looked almost new and were quiet.

 

[jeffescortlx]

For '00-'02, they call out 'Motorcraft SAE 80W90 Premium Rear Axle Lubricant'.

What about the front diff? Same stuff?
... Looks like I have a leaky output shaft seal on the passengers side from axle.

avoid 75W140(for the rear axle) even though it may be suggested...In the past few years Ford had lots of differential failures. There are examples on this board...Does this have anything to do with 75W140? Maybe.

I thought all the failers were from the bearing being made in China by a little 5 year old boy named ching-chow-chang, where he manually forms the bearings out of playdoh and paper mache for 3 cents a day?

 

[gijoecam]

What about the front diff? Same stuff?
... Looks like I have a leaky output shaft seal on the passengers side from axle.

That is for the front... Right from the owner's manuals.

-Joe