I don't think there really is a spot for light pickup truck stuff on this site but not making much progress on Google. Figure maybe someone on here might have some suggestions. Got the 8.8 Ford diff with electronic locker. Last winter the pinion seal started leaking. No big deal, 175k on it so its probably worn out. Replaced the seal and nut with OEM parts. Life was good for 2 or 3 months before it started leaking again. Was a bit overfull so drained it back down to the bottom of the fill plug. No real noticeable leakage until this winter. This time I replaced the yoke, seal and nut, all OEM again. Barely a month later and its sweating again. I checked the diff vent, its clear. Both new seals had sealant on the outside and I lubed the seal lips well with assembly grease. Even used a pinion seal installer tool and it went in square both times. Am I missing something? I've never had a seal give me this much grief with no obvious defects on the parts. The only other thought was since the truck sits outside 100% of the time that it could maybe be the assembly grease starting to thin out and sweat down the bottom of the housing now that temperatures are warm. Its not slinging any oil out, just a damp area under the pinion seal area of the housing and a bit of a dry looking fluid trail down the bottom of housing.
Does it have a dual lip seal, one seals oil in and one seals dirt out? If assembly grease was trapped between the two I could see it doing that.
I honestly can't remember. I searched up the part number online and it certainly does look like there could be a dust lip on there. Kind of hard to tell looking at some of the images.
I did have assembly grease on the seal surface of the new pinion flange as well. There's a big plastic slinger pressed onto the pinion flange, so I couldn't get in there to wipe anything off after assembly.
Sometimes aftermarket is better. Ed
Might be leaking past the splines and not the seal. Some guys goop up the splines with grease, some like to use a little RTV.
Anytime a seal won't last I bad bearings are on the possibles list.
No slop in the bearings that I can feel. Don't think its coming through the splines either, coming from the wrong side of the flange.
I'm going to ask the obvious because I haven't seen it mentioned, is the pinion shaft in good condition with no groove worn in it?
He replaced the yoke.
How many miles after changing the seal and how many long trips? If it isn't leaking to the point it drips, run it for a while longer. If there's no play in the pinion or carrier bearings I don't see a problem if it's only a film. But I've seen input shafts on power dividers with ton's of play and never leak also.
Maybe 5,000 km since the flange and seal were done.
What about running OO grade grease in it? Thin when running but thicker when sitting. There's a name for it I can't remember. Similar to JD cornhead grease they recommend for leaky gearboxes.
Remove the axle vent and make sure the vent is clear with compressed air. Then physically make sure the drain in the housing is also clear.
First thing I did.
Are the U Joints in the driveshaft good? As in, is grease coming out of all four caps when you grease them, or actually take them apart and inspect each cap. Is there a carrier bearing in the driveshaft? Are there any vibrations coming from the back half of the truck underway? Is that electronic locker OE? I can't think of a Ford factory application with an 8.8 with a locker, but I might have forgotten something. What is the year make and model of the truck? Have you had the diff cover off?
It always amazes me how a problem can happen to something that has been around for 100 years but its something totally different and hard to figure out from anything that happen before but also its can be something simple that was passed up before thinking that wasnt the problem. I cant remember seeing a pinion seal on something this new go out unless there was a problem something inside the rear end or something outside caused it.
That's just it, its only 6 years old. I haven't pulled the back cover off but I haven't any reason to suspect an issue back there. U joints were nice and smooth when I moved them around, no slop.
I'll admit last I looked at the axle it was after dark and was using the flashlight on my phone. Was a little PO'd so I just ignored it until today. In daylight it actually looks much less worse than it did with the flashlight. Definitely some weepage but nothing dripping or slinging around under the truck. Guess I'll wipe it off again and just keep an eye on it.
Spray with brake cleaner and recheck later. If it not dripping or slinging oil I wouldn't worry about it.
Of course you wouldn't worry about it- you keep saying you won't work on trucks!
You need to at least remove the rear cover and drain the skunk oil into a clean pan if for nothing else to check for metallic particles and to add some fresh oil. If that rear carrier bearing is going down then it will allow the shaft to tilt and open up a gap on the front seal. Doesn't take much movement to do that and you might not even feel it doing a wiggle test.
And use one of these lube locker gaskets. They are awesome!
I changed the oil about 40-45k km ago. Wasn't terrible. Probably would not hurt to open it up and look again. A lot can go wrong in 2 years of of use.
That's a nice gasket, but the RTV method is like $.75 . . .
But, the labor it saves cleaning the goop off next time, is priceless. By the time I spend 33 bucks on a 7.5 oz cheeze - wiz container of Permatex Right Stuff at NAPA, the gasket becomes very affordable. Especially, if I stop by the necked girl coffee place on the way back from NAPA, for a breakfast burrito and 16oz Americano w/2% (because I’m watching my figure), then I tip the poor girl $10 because She looks so cold. She’s working her way through nursing school is what She told me. Do you have nude baristas in your community? Free gasket shipping from the Zon, to BFE Alaska is just icing on the cake.
Where is said coffee shop? I call BS without pics.
Trust but verify. You are a wise man. North Star Java on Van Horne in Fairbanks. Ironically, next to many of the truck dealerships, lube jobbers and industrial supply outfits. Barista KayLynn will be wearing her nurse outfit tomorrow for the am coffee rush. Tell her that Coaldust sent you. I would probably get banned if I posted a pic, but you can find their Book of Faces, easy enough. Enjoy.
Google says they're permanently closed. There goes the only reason I had to visit Alaska lol.
Let me get this straight, barista named Kaytlynn wearing a nurse outfit that Goog sezz is permanently closed, I must conclude that dive is waayyyy off the radar. LoL.
Under new management, recently. Alive and well.
A business with naked women presumably loses money, thus needs new management. This proves that some people can break an anvil.
Did you change the crush sleeve and reset the preload when you hade the yoke off? No one does it, but ford recomends it.
No, never changed the crush sleeve. I was told the diff needed to be disassembled to reset the preload and I didn't have the time to dive that deep into it. I did use my caliper to measure how far the original nut was installed. I put the new nut to the same depth and then torqued it to spec. Both nuts were the exact same height when I measured them.
I know I have to pull mine. It's got that bearing rumble. I didn't realize the 8.8 was notorious for pinion bearings. But I'll keep putting it off until it costs more. I need to change my ATF as well. They claim those 6R80s need regular fluid and filter changes. Just wondering if I should replace the leadframe while I'm in there, or take the chance that it will never fail.
Your 5.4 cam phasers will Probably fail before the rumbling pinion bearing does.
Everything back there sounds good on mine. Its been a pretty solid truck for the most part.
I got the 5 liter. I got the letter from ford about the extended warranty on the transmission because of the lead frame, but my 10 years are up.
The 5.0 is pretty good for the most part, makes some pretty amazing power for its size. A 5.7 Hemi only makes about 10 hp and 20 ft-lbs of torque more despite having about 14% more displacement.
Never seen them be a problem when one changes the oil and filter every 3k miles with the correct grade and quality.
That's the problem. When I had my Mustang with the 4.6, they pushed the "wait till the car tells you it's time for an oil change". I don't put many miles on in a year. Truck I have now is a 2013, and it only has just over 70,000 miles on it. First oil change on the mustang was over 22,000 miles according to their system. I could hear my father yelling at me from beyond the grave. I do my truck twice a year, when I do the tire swap in spring and fall.