Front Pinion Seal Replacement

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JeepJeepster

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This really isn't meant to be a How-To, just more of 'I did something.'

Front pinion seal has been weeping on my 04 for around 10 years now. While I was under the Jeep working I thought that it may have been covered under the power train warranty but I guess I missed that chance. Lately its started leaving small puddles so it was time to do something about it.

It seems that anything gear related is voodoo which made me very apprehensive going into this. About a year ago my parents 06 WK started leaving puddles and I wasnt about to touch it. With the quadra drive I knew if I screwed something up I knew it would be $$ to have it rebuilt/replaced so I let the dealer replace it. They didnt use a new pinion nut and it does whine a bit. They only charged $150 so Im not sure if they even took the brakes off to get a proper pre-load measurement. This really didnt make me feel like the dealer did anything special. With my KJ I figured worst case scenario I would have to get a front diff from a junkyard.... Plus Ive really wanted to give this a shot.

I followed the FSM to a T and everything seems to have worked great. Ive yet to drive it as I found a torn caliper slider boot and I had to order the boot. I removed the calipers/rotors and I also placed jack stands under the lower A-arms to try and have the least rotating resistance possible. I counted the number of turns that it took to remove the old pinion nut but when tightening it up I was over around ~1/4-1/2 turn to get the same torque. Before removing the pinion I was getting 12.5 in-lb of torque. An 18" pipe wrench worked well to hold the companion flange and it was all I had to get it off with a 2.5' breaker bar. I really wanted to count the turns but an impact would most likely zip it right off.

A seal puller worked ok for removing the seal but I did gouge the inside of the housing. When trying to place the puller near the edge of the old seal it was pulling through the seal, so I had to put the seal puller behind the very outside edge of the seal, right against the diff. The seal was firmly in place. The gouges were behind the mating surface of the seal in an area that doesnt appear to matter. I did wrap a thick paper towel around the pinion to protect the splines.

A new mopar pinion nut, mopar seal, and the miller 8681 seal installer were purchased. The seal installed worked fantastic but you could use a pipe or something the same O/D as the seal. I messed up the front crank seal not long ago and ended up buying the miller installer for it also. The FSM talks of a companion flange puller, a special seal puller, a handle for the seal installer, and a companion flange installer, but I only needed the seal installer. I was able to remove the companion flange with a pry bar by rotating it, prying, rotating it, prying, etc.

When tightening the nut, I was able to easily reach the 12.5 turns that it took to get it off with a 1/2 ratchet. After that it became very tight and I had to use the pipe wrench and the breaker bar to tighten it on up. I would tighten the nut what I felt like was 1/64 of a turn then check the torque with my in-lb torque wrench. After doing this a minimum of 300 times, the torque wrench showed 12.5 in-lb...

Hopefully imgur works ok, this is my first time using it after photobucket went downhill.

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My helper:

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HoosierJeeper

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Did you pack any grease in it to keep that spring band in place while you pounded it in? How often were you checking it/ topping off? Got a slightly weepy one on the XJ now...
 

JeepJeepster

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Did you pack any grease in it to keep that spring band in place while you pounded it in? How often were you checking it/ topping off? Got a slightly weepy one on the XJ now...

Nope, no grease. Is that typically an issue? Ive never greased the spring when installing a seal.

I can only remember topping it off once and that was a few weeks back when I noticed it leaving puddles. The weeping was just enough to sling a fine mist all over everything.

The rear pinion started weeping sometime last year so Ill most likely be doing it soon. Already replaced the valve cover gaskets and the front main seal. Wish it could be more like my 94 ZJ. Only replaced the valve cover gasket and rear main seal on it and it has 255,000mi on it.
 

HoosierJeeper

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I don't know, I was just told when I did one of front axle seals to do that and I did...still ended up redoing it again (at a shop) as the National brand didn't work. Mopar did.
 

JeepJeepster

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Are you sure they didnt mean to grease the lip of the seal so it isnt dry when the install the axle or whatever youre working on?

If you can see it, this seal had grease where the yolk meets up. I still put gear oil on the yolk before I put it in.
 

HoosierJeeper

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Positive. Used this stuff:
Dr. ****** Assemblee Goo

Keeps that spring in place while you pound it in, it's very tacky and then it melts once it warms up.
 

M38 Bob

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I don't know, I was just told when I did one of front axle seals to do that and I did...still ended up redoing it again (at a shop) as the National brand didn't work. Mopar did.

We probably install 50-60 various pinion, axle, trans output, etc seals per year. Never have problem with National, or O'Reilly private label either. Don't recall ever packing back of a seal to keep spring in place.
 

HoosierJeeper

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First time I did it and used National, didn't pack the spring and used the axle socket to pound it in. Leaked just about instantly. Tried it again (used another national seal) and packed it with the assembly go and used a MAC bearing/seal driver and it leaked again after a week. No nicks/gouges anywhere. Took it in and it's been fine with a Mopar seal ever since.

To get them out, the seal puller didn't work at all, I ended up using a gasket scraper to fold it in from the outside and then it came right out.
 

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To get them out, the seal puller didn't work at all, I ended up using a gasket scraper to fold it in from the outside and then it came right out.

I should've used a punch to fold it in like that. Live and learn.

Its all done and back together but I'm not driving it till all the snow is gone. Roads are covered in calcium chloride. Topped it off with oil this evening, Ill see if its leaking from just sitting tomorrow.

Im not saying youre wrong but I cant see how hammering the gasket in would mess with the spring. If its that easily displaced then hitting a really hard bump in the road would cause springs in every seal on the Jeep to go a flying.
 

HoosierJeeper

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Yeah, I think it's more precautionary. Can't hurt.

It might take some driving to test it, but won't hurt to check it after it sits. The axle seals and pinion seal are all above the fluid level so I think they do their job once you're moving and oil is sloshing around.
 

HoosierJeeper

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Pulled my front driveshaft and found some dif fluid. Guess my front pinion is leaking?

Not necessarily. Some is normal. I'd wait till you get a drip that ends up at the bottom of the diff.
 
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