Servicing rear diff - just some simple questions before doing it

[Cobra Jet]

I went to my Ford Dealer today because I needed to get the rear ABS sensor and while there, I asked the Parts Counter person what the rear diff gear fluid weight was so I could also empty & refill for preventive maintenance (and due to accumulated miles).

I was told the rear diff takes 75/140 - is this correct? If it is not correct, what is the proper gear fluid that I should be using? The Ex is a 2004 4.0 w/ 4x4.

Also, if draining out the old fluid and putting in the new fluid, do I need to put back in Friction Modifier or not? I know on the Mustangs (8.8 rear w/ traction lok), those do need Friction Modifier in addition to the gear fluid.


Thanks fellas!

 

[aldive]

I was told the rear diff takes 75/140 - is this correct? If it is not correct, what is the proper gear fluid that I should be using? The Ex is a 2004 4.0 w/ 4x4.!

Yes.

 

[CDW6212R]

Check the axle code, if it has a traction lock then it needs the friction modifier. Use full synthetic gear lube in it also.

 

[aldive]

Be sure you can get the fill plug out before pulling the cover.

 

[Cobra Jet]

Be sure you can get the fill plug out before pulling the cover.

Hmmm... why do you say this, is there an issue w/ removing the fill plug on Explorer rears?

What surprises should I be expecting...?

 

[CDW6212R]

That was a good tip, your plug is in the cover. If you take the cover off first, then you will have a hard time holding it still while you loosen the plug. Just break it loose before taking the cover off.

 

[rumpledoll]

I recently did the rear diff on my 2002 V6 Eddie Bauer. The proper fluid, as spec'd from Ford, is *synthetic* 75W-140 GL-5 oil. I used Amsoil Dead Link Removed. As my Ex has a limited slip D4 differential I also put in 4 oz of the friction modifier that met Ford EST-M2C118-A specification. I found that the diff chattered without the friction modifier.

The rear diff has a fill hole and a drain hole. Several people have reported that they had removed the drain hole first, only to find that they could remove the fill hole, leaving the car in an undrivable state.

I found that the smaller fill hole was hard to remove without the use of a large "breaker" bar. But once I had the leverage it was not hard. The smaller fill hole is 3/8" square and the larger drain hole is 3/4" square.

Rumple

 

[muzzymaniac]

My owners manual states 75w-90...

 

[muzzymaniac]

The rear diff has a fill hole and a drain hole. Several people have reported that they had removed the drain hole first, only to find that they could remove the fill hole, leaving the car in an undrivable state.

Rumple

Am I not reading this right? It doesn't make sense to me

 

[rumpledoll]

Boy I suck in writing clarity, so sorry! The point is this: if you remove the lower drain plug first and let all the gear oil drain out, and then find that you cannot remove the upper fill plug, there is no way to get gear oil back into the differential, which is a bad thing.

Here is a story about someone who had this issue and ended up having the truck flatbedded to a shop.

Rumple

Hmm... I see 75-140 rear, 80-90 front (4x4). But I don't get the drain hole thing either...

 

[Cobra Jet]

Well, actually - if you can't get the upper fill plug out of the rear - there is an alternative way of filling it. Although not the most direct route, but it will work in the event of not being able to remove the upper fill plug...

Remove the rear ABS sensor on top of the pumpkin, insert filling tube and pump the proper amount of gear fluid back into the pumpkin...

Again, only use the above method if you cannot get the fill plug open (and DO use the correct amount of fluid).

 

[rumpledoll]

Good to know there is an alternative to towing! From your post on it sounds like a real PITA, but it's better than nothing.

Rumple

 

[muzzymaniac]

Hmm... I see 75-140 rear, 80-90 front (4x4). But I don't get the drain hole thing either...

Go here -Linky

Page 277

Boy I suck in writing clarity, so sorry! The point is this: if you remove the lower drain plug first and let all the gear oil drain out, and then find that you cannot remove the upper fill plug, there is no way to get gear oil back into the differential, which is a bad thing.

Here is a story about someone who had this issue and ended up having the truck flatbedded to a shop.

Rumple

Crystal clear - great heads up!

 

[mralex714]

There was a TSB on the differentials and the required fluid. Ask the dealer to check the TSB's.

 

[Donner]

Wow!

Go here -Linky

Page 277



Crystal clear - great heads up!

Excellent! I'm going through the entire manual... I'd like to see what else has changed. Thank you