How To: Replace Rear Pinion Seal

STL · #1 11-27-2010, 03:36 PM

Written By: dixie_boysles

Discussion Thread: How To: Replace Rear Pinion Seal

In this How-To, I will be showing you how to replace the rear pinion seal in the 8.8 Rear-end in the event that it is leaking.

Discalimer: Neither I nor FordRangerForum.com takes any responsibility in any damage or actions resulting from this how-to. When performing this how-to, you are doing so at your own risk.

Tools Needed:

safety glasses

gloves (I used Mechanic gloves)

12mm 12-point socket

1/2" drive ratchet

1 1/16" Socket

screwdriver

hammer

vise grips

REALLY big socket or pipe section

caliper set

jack

jack stands

bucket

pipe extension for ratchets

strap

loctite

silver Sharpie

Instructions:

First find a good place to work on your truck, preferably a good flat concrete surface. Chock the front tires and place truck in park and set parking brake.

Then using the rear differential as a jacking point, jack the rear-end of the truck up to desired height and place jackstands under axle at U bolts and remove the jack.

Using the Silver Sharpie, mark the position of the driveshaft to the flange by making thin smooth, accurate lines; I made two marks and put a number beside them:

Now using the 12mm 12-point socket, 1/2" drive ratchet and pipe extension, loosen the driveshaft bolts. You will have to undo the parking brake and put in neutral to turn the driveshaft to get to other two bolts of driveshaft. Remember to re-apply the parking brake and put back into the "Park" position when done.

Once bolts are out, tie or strap the driveshaft out of the way like so:

Now that the driveshaft is out of the way, time to mark the flange and pinion nut. Again, using the Silver Sharpie, make thin accurate marks marking the position of the nut to the stud to the flange and the position of the flange to the differential housing:

Then take your calipers and measure the distance the pinion stud protrudes from the nut. My set was not measuring right so I just locked the calipers once i got the distance measured:

now place your 1 1/16" socket on the nut and mark its position to the the mark you made on the flange:

First place bucket under flange to catch any oil. Using your 1/2" drive ratchet, and making sure your parking brake is set and that you are in park, loosen the nut. You may have to use the pipe extension to get extra leverage on it. Now while turning the socket, COUNT how many revolutions it takes to get the nut off using your marks as references. NOTE: DO NOT LET THE SOCKET COME OFF OF THE NUT OR YOU WILL LOSE COUNT.

Now you must get the flange off. You can do this two ways, you can use a big ass hammer like I did OR use a pulley puller. If you us a hammer make sure you dont hit one side too much to get it off.

Time to take the seal out. I used Ford's recommendation of Vise Grips and a hammer and a screwdriver. Take the screwdriver and hammer and raise the lip up of the seal. It will be up against the diff. housing. once you have it lifted up, take the Vise-Grips and tighten them on the lip. Then take a hemmer and hammer the Vise-Grips towards the front of the truck and the seal will pull out.

Clean the area up with a rag and now its time to put new seal in. Take a little oil and placing it on the black rubber on the seal like you would do an oil filter seal. Firmly place the seal into place but do not force it in; just get it seated.

Now using the REALLY BIG SOCKET, and a hammer, place the big socket on the seal and hammer it down until the seal lip is flush with the differential housing. Be careful not to hammer one side in too much at one time, it needs to go in equally or you will be buying another seal:

(Sorry this pic is before I hammered it ALL THE WAY DOWN, make sure the lip of the seal is flat against the housing)

And your new seal is in!!

Now put the flange back in using your marks and then use the hammer and REALLY BIG SOCKET to hammer it back into place.

Then using the marks on your socket, nut, and flange, put the stud nut back on the same amount of revolutions it took to get it off. Then check to see of your stud distance is the same. It took me almost 17 revolutions to get mine off so I checked the stud depth at the 15 and 16 revolution mark to be certain. Once everything is aligned back up, unstrap driveshaft and bolt it back up. Before putting the bolts in, place a little loctite on them and make certain that you align your driveshaft marks up you made earlier:

Now just put everything up and let the truck down and you are good to go! Now this may/may not be the exact way to do things, but after research and looking at the Ford Workshop manual, this is the way that I did it.

Now you will have some oil that leaked out of your rearend in the bucket. At this time i just put that back in the truck as i drained it in a clean bucket. I will be replacing the rear-end oil soon, so its not a big deal. it it best to replace oil when doing this, but that is a writeup for a different time.

A big thanks to Justin Higgs for his writeup and information as well as STL (Mykhael) for all the texting help he did.