Anyone know what the oil capacity is of the front/rear diffs? I've searched and came up empty handed. I plan on using Mobil 1 Synthetic LS 75w-140w in both.

Thanks!

 

it doesn’t matter... supposed to fill it up til it starts coming out of the fill hole. Thats probably why you couldn’t find much on the capacity ...That’s how you know it’s full. Make sure you need limited slip oil or not because that does matter...look on your diff tag in the rear and if it has LS on it then limited slip is required. But for the front it probably isn’t required to put LS oil in the front as it is an open diff...

 

Him using Mobil, modifiers' not needed

 

The front rear wouldn't be an LS if the rear one is?

 

Certainly not on the front. Unless its been modified, its an open rear, as probably 99% of all front diffs driving around are. However, if the rear IS a limited slip, then it is possible that additional friction modifier MAY be required. For many people/trucks, the additive pre-mixed into many popular synthetic 75w140 gear oils which include the friction modifier ( not all do) is enough. But, if you still get clutch chatter and undesirable lockup when cornering, then you may need to add a little more. Of course, the trade-off for smoother engagement is more clutch wear and shorter life of the LS.

No. See above. Highly unlikely. It certainly never came from the factory that way. A small number of "off-roaders" will put a LS, or more commonly a locker, in the front diff, for better traction off-road, in mud and rocks. However, doing so can cause for some very weird behavior/steering on pavement; especially with a locker, as you are now messing with the steering axle and altering or eliminating the front wheel's ability to turn at different speeds (which is essential to turning).
Of course an LS or locker in the rear imposes that same limiting factors, BUT the front wheels, since they do the steering, will normally see a much greater side-side difference in turning radius/speed around a corner.
Using a 75w140 in an open rear won't hurt anything, other then wallet. In fact, I use it in the rear as it is A.) a synthetic and B.) a little better protection at higher temperatures/speeds (75w140 )
Although, its probably a little too heavy for the front diff, considering it sees little high speed/hot weather use. I run a good synthetic 75w90 or 80w90 in the front.
I have used Royal Purple, Lucas, and Mobil 1. They are all good.

The Sterling 10.25/10.5 rear diff takes just under 4 quarts.

The commonly published spec for the Dana 50 front is = to just under 2 quarts. However, that does not get it filled anywhere near the fill plug. Many people believe it to be an error/misprint. The Dana 60 spec is just under 3 quarts. In my personal experience, the Dana 50 will take about 2.5 - 2.75 quarts to fill to the plug. As far as I know, the D50 and D60 use the same case, so they SHOULD have the same capacity.
Be warned though, if your inner axle seals are bad, overfilling will make that obvious. You will have puddles under each front knuckle by the end of the day, and a big new project on your list. Oh well, better to find out sooner rather then later I guess.

 

Exactly what I needed. No point in buying 9 quarts of synthetic stuff if 3 will do, haha!

Have a happy New Year everyone!

 

Save this link, part #s and capacities


http://www.powerstrokehub.com/7.3-power-stroke-maintenance.html

 

 

I've got the standard cover, I think.

Uh....How about another dumb question? Do we have D60's (carguy's post above) or D80s in the 4x4s?

 

D80 is the REAR axle used in dually F250/350's

Up to sometime in 2001 (I guess until they ran out of D50 parts), F250's had a D50 in the front and F350's had a D60
After that, both F250 and F350's had a D60.

The case/housing is almost the same. ( There are some difference apparently, in the machined area where the inner seals go, as they require different tools.)

Everything from the knuckle out is identical, including the u-joints and stub shafts.
The inner axle shafts are different. The D60 shafts are larger diameter, and higher spline count where they go into the diff.

I believe the D60 has a larger ring gear.

Some people with a D50 like to "upgrade" to a D60. But, for the vats majority of us, its not needed. The D60 is slightly stronger, but the D50 is by no means weak, and will hold up just fine for normal street use. Unless your front axle is trashed anyway, or you plan on doing some heavy off-roading, I wouldn't waste time or money worrying about it. If you did find yourself needing a front axle, then I would get whichever was readily available/cheaper. Externally, they are interchangeable, so you can swap either way.

 

So for 2000, D50 front, D60 rear?

 

I am under the impression that the back rear in our trucks is a Sterling. I am curious to know if they are different between the 250 and the 350 model trucks.

 

 

My F-350 SRW parts truck has a Sterling in it, is it the same size as the Sterling in my F-250?

 

'99-'10 SRW F250/F350 SuperDuty trucks have a 10.5" Sterling in the REAR
'99-'10 DRW F350 SuperDuty trucks have a Dana 80 (D80) REAR


SRW '85-'97 F250/F350 OBS Trucks had a 10.25" Sterling REAR - I'm not sure about the DRW, but I think they were also 10.25" Sterling, with different housing and hubs ( tube and axle lengths)



'99 - sometime in '02 F250 SuperDuty trucks had a Dana 50 (D50) solid axle front.
ALL Excursions have a D50 front. They never got the D60.

'02 -'04 F250 have a Dana 60 (D60) front axle
'99-'04 F350 have a Dana 60 (D60) front axle

'05-'10 F250/F350 have a coil spring Dana Super 60 front axle.