Gear oil

[ChrisP Riley]

Just wondering what kind of weight oil to use when changing the oil in the rear end??? I will be using synthetic but not sure what weight. Any help will be appreicated......Thanks... 2001 S/T

 

[Todd Z]

I think the synthetic is 75/140 and you must add a bottle of friction modifier FIRST if you have limited slip..

Todd Z

 

[Johnny O]

My owners manual was a little confusing on that point, on one page it said 75w-90 and on another page it said 75w-140. I used the 75w-140.

 

[Kevin Palmer]

My manual is like Johnny says. Had two different grades listed. Found out that one is for Limited Slip and the other is for an Open Rear End...

 

[Rodger Tellefson]

I'll be putting in Royal Purple Max Gear.

 

[Kevin Palmer]

A little hard to read due to how it pasted here.



Rear axle

lubricant (Foot Note 5)

Motorcraft SAE

80W-90 Premium

Rear Axle

Lubricant

Refer to

Footnote 6





Motorcraft SAE

lubricant (Foot Note 5)

75W-140 High

Performance

Synthetic Rear

Axle Lubricant

Refer to

Footnote 7



5. Fill to 6 mm to 14 mm (1/4 inch to 9/16 inch) below bottom of filler

plug hole.

6. For vehicles equipped with a conventional rear axle, refer to your

scheduled maintenance guide for axle fluid change intervals.

7. Vehicles equipped with Traction-Lok axle require synthetic rear axle

lubricant. Rear axles containing synthetic lubricant are lubricated for life.

These lubricants are not to be checked or changed unless a leak is

suspected or service is required. The axle lubricant should be changed

any time the axle has been submerged in water.

Add 118 ml (4 oz.) of Additive Friction Modifier XL-3 or equivalent

meeting Ford specification EST-M2C118–A for complete refill of

Traction-Lok axles.

 

[Johnny O]

Mine didn't specify a different weight for open and L/S axles, only the friction modifier.

 

[Kevin Palmer]

The cut and paste above is out of my 03 manual....

 

[Stephane Bolduc]

Don't want to hijack the thread, but when is it recommended to be done ?



I have 67k on my '01 and just did the trans. fluids, but I wasn't planning to do that one just yet, I was under the impression it was somewhere around 100k. I will however take care of the cooling system this month.

 

[Todd Z]

Steph, Yes, the gearboxes are (as recommended by ford) every 100K....

I would recommend every 60K to be safe..

Todd Z

 

[Stephane Bolduc]

Thanks! And is it as messy as the transmission ? Should I go for a drain valve like I did for the transmission ? Looks like this once will come down more straight; since it is already aligned towards the bottom and not as wide.

 

[Dallas Starr]

I coincidently just did my rear diff last saturday and switched out to castol syntec gear oil. (I was at 160k). I took a peak at the front diff and it looks impossible to get thepan off so I went to my local lube-x here in edmonton and if I supply the oil they'll suck out the old stuff and put in mine for 25.00 even.





Dallas

 

[ChrisP Riley]

Thanks guys for the help!!! I do love this website!!!!!!!!!!!! Later on....Riley

 

[Bob R]

So would it be ok to use Mobil One 75-140 wt. synthetic lubricant on an open rear end? Thats what I just did. Now I wonder if I should drain and refill with 80-90.

What do you all think.

Thanks,

Bob