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New issue: front gear differential seal leak
- Thread starter Last Ride Bronco
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So, I thought I was being proactive and ordered two front diff pinion seals (#MB3Z-3254-B) from Tasca, but they replied with the following today:
Try ordering from one of the other online dealers that show up in the internet part number search results. Tasca was MIA and radio silent after I placed an order online a few months ago. Their website generated a zero for an order number and contact attempts were unsuccessful. I was never charged anything but perhaps they just don’t want to fulfill some online orders but enjoy the web traffic pushing business their way online and offline. Fairway Ford Parts has competitive prices, fair shipping, in-stock or sourcing availability/willingness and a very responsive parts representative via email.
Finished up my inspection today of my front diff leak (and 7MT grinding noise). Front diff leak being covered under warranty, and a variety of parts ordered for replacement. One of the parts on the list I saw was the front differential carrier (#MB3Z-4141-C). I haven’t seen the full part list for the repair, but hopefully they’re replacing the pinion seal itself along with the carrier. Would any other folks who’ve gotten this fix done have their full part sheet handy?
Interesting … my parts list from my dealer for this warranty job is a bit different. They’re also replacing the differential carrier (see above).Here y’all go.
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While waiting for my parts to arrive to replace the pinion seal, I decided to try and refill the diff to see how much fluid has leaked out so far. Out of the roughly 1qt (32oz) it's supposed to take, it only took about 6oz of fluid. Not great, but not awful. Will probably fill it up again in a week or two to try and gauge how fast it's leaking.
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#MB3Z-4141-C is the entire front axle assembly. You're getting a new front axle. The pinion seal already comes installed as a full unit with this part number. They will not replace the axle shafts. It is a fairly straightforward install, I had the same thing done by my dealer. It took 20 days for the axle to come in. I dropped mine off at 8am and had it back by 3pm fully tested. They initially told me 6 hrs labor but I don't think it even took them that long.
The fact that it's not just my dealer replacing the whole axle for the pinion seal leak, leads me to believe that Ford is now telling the service departments to just replace the whole thing, even though there is a part # for just the seal. The main thing in my mind is that they could have found that there was some quality issue with the supplier (Dana) installation of the gears or possibly pinion bearing issues. If it were just a problem with the seal, they would only replace that; it is a cheap part and not nearly as much labor to replace. But pinion seals failing even in the first 100k miles is not normal, and leads me to believe that they discovered issues with the diff internals on these units.
I'm guessing the yoke flange was not machined to the correct surface finish and is eating the seals.
My m210 was bought via CJ Pony Parts as a Ford Performance part and they're saying I have zero warranty on it.
Add me to the list of 10Kmi seal failures.
I was able to order a Spicer seal from Rock Auto after not finding any at my usual dealers sites. $38 after postage - should be here Monday. I can send the yoke for a ride in the lathe to fix it if that proves to be the problem. I sure hope it's not the pinion bearings.
even with the factory warranty there might not be much hope for fixing this — I’m still waiting on my replacement diff to come in many weeks after getting it inspected by my dealer.
I'm guessing the yoke flange was not machined to the correct surface finish and is eating the seals.
My m210 was bought via CJ Pony Parts as a Ford Performance part and they're saying I have zero warranty on it.
Add me to the list of 10Kmi seal failures.
I was able to order a Spicer seal from Rock Auto after not finding any at my usual dealers sites. $38 after postage - should be here Monday. I can send the yoke for a ride in the lathe to fix it if that proves to be the problem. I sure hope it's not the pinion bearings.
Unless you fall within the vin# range of possible problematic 2.7 engines I would not worry too much about it from what I have heard. The 2.7 is an excellent engine. Its well designed and engineered and well built for the most part. Could it be better? Hell yes, the engine bay is a mess and it could be simplified significantly but as it is now one has access to most things easily. I am wondering when will Ford make some improvements to the Bronco drivetrain. We are on year #3 so maybe in 2 more years?
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I was looking at the SEMA video where the Dana rep was talking about how they reduced seal pressure to reduce drag to increase fuel economy as part of the Advantek changes and that might be the culprit here. There does seem to be a part number change on the seals as well.
Combine that with the national backorder on the seals and that could explain swapping the whole unit instead of just the seals? Trying to keep trucks on the road and owners happy vs extended down times for a $20 part.
I'm not sure Ford would admit to either scenario, but maybe their supplier agreement means Dana eats the bulk of the expense anyway? That's all hush hush industry NDA territory I'm sure.
We'll see what I find when I pull mine apart Monday.
FedSux has been sitting on my seal all weekend, and we have a big storm coming tomorrow when it "should be" on the truck driving up 4 hours from the MPLS hub. They already changed it's delivery from tomorrow to Tuesday, and now God only knows when I'll see it. 
Thankfully, despite peeing copious amounts of gear oil all over the bottom of the truck, the diff seems to be running cool enough I shouldn't have any concerns with bearings losing temper or whatnot. So that's a plus!
I'll keep y'all posted.
Thankfully, despite peeing copious amounts of gear oil all over the bottom of the truck, the diff seems to be running cool enough I shouldn't have any concerns with bearings losing temper or whatnot. So that's a plus!
I'll keep y'all posted.
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Is this a hard DIY repair or fairly easy? Could you document it? I have a feeling someone will need this info later on.FedSux has been sitting on my seal all weekend, and we have a big storm coming tomorrow when it "should be" on the truck driving up 4 hours from the MPLS hub. They already changed it's delivery from tomorrow to Tuesday, and now God only knows when I'll see it.
Thankfully, despite peeing copious amounts of gear oil all over the bottom of the truck, the diff seems to be running cool enough I shouldn't have any concerns with bearings losing temper or whatnot. So that's a plus!
I'll keep y'all posted.
Generally, it should be easy. You need a 3-jaw puller to remove the "yoke" (which is flange shaped on these CV joints) after removing the pinion nut.
Once the yoke is off, the seal is just pressed into the diff housing. Use a screw driver or pry bar to extract it, clean the housing off, then use something (OD of the seal mounting flange is 3") to evenly drive the new seal back into the housing until flush (large socket or section of pipe - buy a "nipple" at your box store of choice for a couple bucks). Put a nice coat of gear oil on the new seal lips, reinstall the yoke, then tighten the nut back to where it was (you want to take a pic before removing the nut and mark the two with a punch so you get it back at the original pre-load).
Put the driveshaft back on and you're done.
The photo makes sure you have the same number of threads exposed. The punch marks ensure precision of the final torque.
If you were doing this on a bench or with new bearings, you'd tighten to a rotating torque of about 40 in-lbs drag, but that's to set the crush sleeve between the inner and outer tapered roller bearings. Since we're not messing with any of that, setting it back where it was is the way to go. You'd need to pull the stub axles to use the rotating torque method.
All that said; I had to insert my drive shaft into the yoke before mounting my diff as the drive shaft was slightly too long to stick into the yoke while the diff was mounted. So I'll find out if that's still the case now after the CV's have broken in or not.
You will need a screw driver or pry bar to remove the drive shaft CV cup from the yoke. Just use the access slots to pry on the mounting flange away enough to get under it and work it off from the edge, you don't want to pry against the domed surface inside the yoke. It won't take much force, but it won't just flop out once the mounting bolts are removed either.
Hopefully that helps.
New seal finally came today and removal of the yoke revealed that the Bars Leaks was doing it's job after 2 applications - there was a "band" of sealer material deposited at the sealing surface on the yoke.
There was no damage or any evidence of improper or poor manufacturing. The seal surface of the yoke was a very fine surface, clearly finish ground, and measured just shy of 2.129" OD: for a .0045" interference fit with the seal glands. This is all kosher in my book.
The pinion nut is 1.25" btw.
There was no damage or any evidence of improper or poor manufacturing. The seal surface of the yoke was a very fine surface, clearly finish ground, and measured just shy of 2.129" OD: for a .0045" interference fit with the seal glands. This is all kosher in my book.
The pinion nut is 1.25" btw.
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