Rear Diff leaking? Or not...

[Black_Sport]

Hello All! - I noticed a spill in my garage a few weeks back and cleaned it up. Then noticed it again, again, again. About the 2nd time i noticed it I looked under my truck and saw that my Rear Diff looked covered in oil. I thought "i should fix this" well that was about 3 weeks ago and then i went on vacation and camping and this is the first time i have had a chance to look into it.

I have a 2002 Ford Explorer Sport Trac 2wd about 111k miles. I bought it and i believe it has had some engine work but it runs good. Only have had to change the thermostat.

Here are some images of the issue. I think it is more than the Rear Diff and need to know if I should be able to fix this or put some fluid into it and take it to a transmission specialist? I haven't had the trans flushed so if I have to have work on it I'll just add that to the bill.

If you look at the pictures they all still look moist so it is a good size leak and even the part that connects to the rear diff looks oily. HELP!

 

[ncranchero]

Well, I'd say you have yourself a leaking differential pinion seal. It's not on the driveshaft that I can see, only on the yoke. The leak is black and not red or brown as transmission fluid would be.

 

[Black_Sport]

now how hard would that be to replace? I've not some googling and can't come up with much direction.

 

[ncranchero]

Here's a thread on replacing the pinion seal in a Ranger which should have the same 8.8 rear as your Explorer.

how-replace-rear-pinion-seal

 

[Black_Sport]

This is awesome, I believe I can do it. The only issue is I can determine how much or what type of oil to use. Since my truck had some work the sticker isn't in the drivers door so I don't know how to determine the type of rear diff oil.

Ideas?

 

[Black_Sport]

So I figured it out. 3L73 and says use 75w140 synthetic only then additive.

Thanks Steve!

 

[Black_Sport]

follow up: Ordered the parts from Advance Auto Parts online.

2 qt's of Mobil 1 75w140 that has the Additive in it $18.99 (total 37.98)
1 Seal I believe part #3604 - $10.29
RTV Silicone Gasket - $3.79
Sub Total: 52.06
Less Coupon: 20
Total = $35.03

I'll pick it up tomorrow and let everyone knows if it was worth $35 or if I should have just taken it and been charged $120.

 

[Black_Sport]

Mission Complete. Took me about 3-4 hours I changed the Seal and the Differential fluid.

Note I didn't have a HUGE socket so I had to build one. I took a 4x4 about 5 inches long, drilled out the middle so the bolt wouldn't be in the way. This worked perfect for both parts.

Thanks a lot for the instructions. Well worth my $35 investment! (or we will see )

 

[Clusterpup]

Only two quarts? That limited slip gear must take up a lot of space.

 

[ncranchero]

Lubricant Fill Level Checks

Additive Friction Modifier C8AZ-19B546-A 118 ml (4 oz)

Rear axle lubricant 2.3 liters (5.25 pints) with Traction-Lok® axles.

2.4 liters (5.5 pints) with conventional axles.
Rear axle lubricant level 6.4 mm (0.25 in) to 14.3 mm (0.57 in) from the bottom of the fill hole


Ford Motor Co service manual

 

[Black_Sport]

I used this: http://shop.advanceautoparts.com/we...ALUE3-_-VALUE4&ci_src=14110944&ci_sku=7070076

2 bottles = 2 quarts = 4 pints. So i'm prolly running a little low right now. I'll get some more and put in there.

Thanks again