leaky 8.8 rear differential pinion seal | Ford Explorer Forums - Serious Explorations

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leaky 8.8 rear differential pinion seal

crossbones

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OKC, OK
Year, Model & Trim Level
2001 Sport Trac
Hey guys need help, I have a 2001 Sport Trac and I am having problems with an 8.8 limited slip rear differential pinion seal leaking. Do any of you know if I can change this seal without having a problem with the preload on the bearings? I read where this can be a big problem if the preload is not set right.
If it is not a problem setting the preload, then how do I keep from getting the pinion nut too tight or too loose?
 



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The real way of doing it would be to replace the crush sleeve but half the people just throw in a new seal and call it good.
 






8.8 rear differential pinion seal

Rather do it right than half right but do I need to be concerned with the preload?
 






You want to mark the position of the nut on the pinion as well as count how many turns it is threaded on. If you put it back together the correct amount of turns and the markings line up it should be fine.
 






That's what I was hoping to hear. So you also think it's a good idea to replace the crush sleeve?
 






That's what I was hoping to hear. So you also think it's a good idea to replace the crush sleeve?
Well, they take a few hundred ft-lbs to crush and to measure the pre-load you need to remove the carrier/ring gear, so it's a lot of work.
 






Its a good idea to replace the crush sleeve but as HahnsB2 stated, it is too much work. The Ford 8.8 is a great axle but the crush sleeve is what I hate the most about it.
 






Mark the nut and pinion as was mentioned. Actually, you really should replace the nut too, but in this case, it would be nearly impossible to reset the crush sleeve. Clean the pinion threads and the nut, use locktite, and put it together. As you get close to the mark, you can feel some fore and aft movement in the pinion. As you hit your mark, that should be gone. If not, then you either need to keep tightening, (not recommended) or pull it apart and find out why (best practice). I always go just a tad past the mark to make sure I have the right preload on the bearings. But I've been doing this for over 35 years and have a pretty good "feel" for the job.

Most important...why was your seal leaking? Seal just finally die? Groove in the yoke? That MUST be fixed with a speedy sleeve or you will have another leak immediately. Or, are you bearings wearing out and allowing the pinion to move around and leak past the seal? This is what you must decide before arbitrarily tossing another seal in it.
 






leaky 8.8 rr diff pinion seal

Thanks for all the good detailed info. I will do a close inspection after cleaning and hope that it was just a bad seal. Sure am glad I found you guys and I appreciate all the good help.
 






My seal was bad, and I replaced it myself. There was a groove in the flange, so I replaced that. It started leaking again, and I pretty much killed the inner bearing. So, I messed it up and picked up a used axle. I should just taken it to the shop. But that was before I found this place and had all of these experts telling me what to do. :D I also beat the flange off with a hammer. :hammer: That probably was not a good thing. Oops!
 






Believe me...there are a kazillion vehicles running around with flanges that were knocked off with a hammer. :)
 






The first time I replaced a pinion seal I replaced the crush sleeve, the car was on jackstands and I almost tore my arms off doing it... the second time I reused the sleeve, It's still going many years later. If your rear end makes any noise after you do it take it to someone with rear end experience to check your work... that sounded kind of strange didn't it...
 






I did take mine to a shop - I asked them to set the preload. They kept it for a day, did nothing, and tried to get me to pay for a rebuild as "the only right way to do it". I told them where to go, and thanks for wasting my time, and drove for many more miles before it leaked again. One day I'm gonna take it apart and check it out. It's in my shed.
 






Yeah, it can be hard to find a trustworthy mechanic sometimes.

Is the preferred method of checking still running torque? I remember using an inch pound torque wrench spinning the pinion to check the preload. Seemed strange at the time but I guess it works. I haven't done anything other than an 8.8
 






hi guys!! looking for pre-load torque specs
 






actually the car is already tore apart the new seal is in!! now reading this i should have mark the thread count?? i thought i could just set the pre-load?? yes or no??
 






also i was reading that i need to replace the nut because it has tapered threads 1 time use?? is this right!!!
 






You "should" replace the nut, per spec. Not sure of the preload setting. It's been a long time, but you'd need a dial type torque wrench to set it.
 






thanks joe, i did have to change the nut it did come loose
 



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