Rear Diff Pinion Seal Replaced...No more leaking
 

Well the pinion seal has been replaced. Decided to do it myself rather than pay $165 (parts & labor)…mainly because my brother was on hot standby 800 miles away and I could call him the moment a problem would arise. :-blahOnly had to call him a couple of times. The Pinion shaft nut took a 1 1/8” socket. I had to use a propane torch to heat up the four 12pt 12mm Driveshaft support bolts before I could back them out. I used the count the turns of the nut method after marking the pinion shaft and yoke and socket and …you get the ideal…The main headache I had was the Yoke companion flange…it did not want to come off easily:-banghead…so I had to employ a gear puller…still with the puller and tap as I went along, it took approx 45 minutes to finally get it off :-X09(my brother thought this was peculiar). Old seal came out; new seal went in (textbook). Put the Yoke back on and tightened her back with the same amount of turns that came off…plus a scoatch….torqued down the driveshaft bolts, topped off the pumpkin and scrubbed the under carriage to clean off the splattered gear lube. No leaks. :-X24 <!-- / message --><!-- BEGIN TEMPLATE: ad_showthread_firstpost_sig --><!-- END TEMPLATE: ad_showthread_firstpost_sig --><!-- sig -->

Thanks for the scoup on how this was done. I was wondering. If mine leaks I will do it at home now.

That is the way to do it...now just monitor.

iron1951...just as a sidenote...by scoatch I mean 1/16th of inch. Once you pick up the new seal...compare it with the old one still seated, so you know what parts come out and what stay. That way you know where to get a needle punch under the lip of the metal outer ring...once I got that bent out a little I grabbed it with visegrips and hammered the visegrips shaft to pull the seal out (this is right out of the manual). Putting the new one back in (after lightly greasing the outer metal race and inner rubber ring of the new seal) was accomplished by holding in place with the left hand using a block of 1"x2" wood and tapping in with the right hand...or reverse if you're a southpaw. Make sure it seats fully and you're good to go.

Nice write-up, my pinion seal is seeping a bit and I will be doing this SOON!! Thanks:-X04

be sure to mark your driveshaft location before remove. that is about the only thing I think he did not mention.

senix...thanks for pointing that out...I did use a paint pen and marked the driveshaft orientation to the yoke companion flange...I even went as far as individually marking each of the four 12mm/12pt bolts with paint dots 1,2,3, and 4 to ensure they went back in the exact bolt holes they came from. Kinda anal, but I didn't want any problems later on.

it good to be aware of driveshaft orientation, but the only time it is of concern is if you pull a slipjoint apart. the issue is when 2 adjacent ujoints are not in phase. what i mean is that if you take a driveshaft with 2 yokes they must both have the crosses the same.if the front cross is facing 12 and 6, the rear one must be the same. it is possible to be off by 180 degrees so its good to use a paint marker or punch to mark the join at the slip joint. 180 is not horrible but it throws out the balance job, sometimes it'll vibrate sometimes its ok

The slip joints in SuperDutys have one spline that's twice as wide as all the others, effectively "keying" the two pieces, and preventing you from mating them in any other way than how they're supposed to be.

You're only going to get it back together one way. The correct way.

Pop

i have changed the pinion seal in my f250 also,but am running into problems replacing the pinion flange. it will start a lil but thats all. i bought a new flange from ford and no luck.

jayford. Once I placed the yoke flange back on the pinion shaft splines I had to tap (not too hard) it until I had a couple of rows of exposed thread IOT get the pinion nut started. Once I got the nut started I just worked it around counting back the same amount of turns it took coming off....it will actually walk the yoke companion flange back onto the pinion shaft and tighten up like its supposed to. Good luck.

I have fixed hundreds of rear ends and counting the threads to get the nut back into place is a bad idea. You are not accounting for any wear of the pinion bearings and the possibility that the nut has backed off. Chances are the seal was bad in the first place because the pinion was loose. Thats like putting your boot laces back to the same tightness after going half way through a hike. Tighten the nut down until there is a slight drag on the yoke (like it is supposed to be). Go slow here so you don't have to back the nut off to attain the drag.:-X16 Not only have you not accomplished anything but now the nut is loose and prone to backing out. Use a seizing compound also.

EXv10...you're one of those rolling torque guys huh? So what you're saying (which differs from very many both on this forum and other sources) is that everyone should just go to the dealer to get the repair done....wrong answer. DIY....they do it EXACTLY as I described...I checked two local dealerships and 2 independent mechanics ....Why pay +$165, when the part cost $17. Jayford ...DIY, don't listen to EXv10...unless he's willing to share by breaking down his method for you in detail on this forum. lol

Who said anything about going to a dealer? Your post makes 0 sense to me?????????????What rolling torque????????? What part costs $17? Are you a mechanic?...........Your truck is pretty cool with that locking gas cap LOL

Easy guys !
i've done them both ways (rolling torgue or nut torque).
But in a pinch done his way also.
Being a retired ford tech ,you find ways to beat the slt times given by ford to make money.
Never had a comeback on either way.
A key thing to remember about pinon seals is if the seal runs dry an scores a groove in the seal surface ,it will leak again in a very short time.
If you reused the same pinon nut you had better chk on its tighness down the road .
They are not to be reused. they are like a nylock nut.one time only

If you need or want the written way for proper rolling torque or nut torque ,I will explain it .

Rich