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Rear diff cover leaking

6K views 7 replies 4 participants last post by  EscaladeSteve 
#1 ·
Took a quick look & looks to be leaking out of the bottom of the cover. Pretty sure that's where its coming from & it's not from the pinnion seal.

Anway does this video pretty much cover everything I need to know on how to fix this?POWERSTROKEHELP.COM - The Information Source for Ford Power Stroke Diesel Owners

If not what else should I be aware of or be looking for?

Is it unusual for the cover to leak? Is that an indication of another problem or is it like everything else & eventually will leak? I have no idea when the last time the fluid was changed.

Thanks for any help.
 
#3 ·
The video won't show for me here at work. So I can't say anything about that. It can be common for just the pan to leak, which is no big deal. If you don't know when the fluid was last changed, I would change it even if the pan wasn't leaking. I just did both my differentials because I just purchased my truck, and I replace all fluids and filters from the start so there is no guess work.

They sell a paper gasket at Checker for the real differential. I used it along with RTV to redo mine. The front didn't come with a gasket, and I just used the RTV to make the gasket. You also need to check and see if you have a limited slip differential in the rear. If you do, then you will need to add a friction modifier to it unless you purchase some gear lubes that advertise that you don't need it with their lube (such as Amsoil or Royal Purple). Your differentials also require synthetic lube as well. Hope some of this helps.
 
#4 ·
Well I got under the truck & took a better look & the leak is coming from the front of the differential where the driveshaft connects, running down the bottom of the rearend & dripping off the bottom of it where the cover goes on. So I guess this means its the front pinion seal right?

How do I change that?

I checked on the tabs on the cover & one tab says 75w 140 SYNTH oil only. So I just get that oil & no friction additive needed right cause its synthetic. The other tab had wrote on it S409H731051a10. Is that enough info to tell what kind of diff I have?
 
#5 ·
What are the torque specs on the nuts & bolts I will have to remove? Do I need a puller for anything?
 
#6 ·
I don't know the torque specs offhand. Just because you use synthetic, doesn't mean a friction modifier isn't needed. Just certain brands of synthetic (like the Amsoil and Royal purple) "advertise" that you don't need to add any friction modifier. I guess basically because they already have special additives in them already. There are more knowledgeable guys about this subject than I. Hopefully they will chime in.

P.S. I used Amsoil in both my differentials. So far no issues that I'm aware of.
 
#7 ·
Well I bought some gear oil to at least top up the differential until I can get it fixed. I have drove quite a bit since I noticed it leaking & topped it up this morning & it didn't take hardley any to fill it.:confused: So i got looking around under the truck & perhaps may have put 2 &2 together. I noticed that the skid plate on the fuel tank is wet, the tranny skid plate is also wet. I have a modist leak in the bottom of my oil pan which now I am wondering if this could be the oil I am seeing on the differential. I''m guessing the oil is leaking out of the pan as I am driving & getting blown back over the skid plates & the back to the differential. I smelled the oil on the diff & am not sure if it is engine oil or not but it sure doesn't stink like the gear oil in the diff or the gear oil I bought to top it up. If this is engine oil then it must have been doing this for a long time & I just didn't notice it on the diff.

I guess I will just drive it for a while & check the fluid level in the diff. If it doesn't go down then that must be what it is.
 
#8 ·
I definitely have a leaking diff cover and it's definitely gear oil. Tonight after the sun went down I crawled under the truck and removed the 9 bolts that hold the cover on. Whoever was in there previously was nice and generous with the rtv gasket sealer and the cover is impossible to remove. I even beat on it with a rubber mallet and it wont budge.

Anyone have any suggestions? Maybe put a little heat on the cover with some map gas?

By the way, i'm just kidding about the 9 bolts...there are 10...just seeing if you're all paying attention. And yes, even with all 10 removed, the cover wont budge.


Oh, when i pulled my magnetic fill plug, it was covered with metal shavings and from what I can tell, most all of my gear oil has leaked out. I noticed it a couple days ago so I have only put on about 60 miles since noticing the drip. Hopefully everything will be ok in there.

Any suggestions for getting that cover off are greatly appreciated!
 
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