Front Diff Pinion Seal

grabeb

TJ Enthusiast
Original poster
Joined
Jun 29, 2021
Messages
373
Location
Kansas
This weekend I was changing oil, lubing the chassis and replaced the front track bar on our 01 Jeep TJ. I noticed it appears there is fluid dripping either from the pinion seal or the diff cover on the front diff. Trying to determine which one. I sprayed a bit of carb cleaner to see if it would clean it up enough to watch, but didn't do much. I figure I'll use something more suited when I have a few minutes. The Jeep has about 125,000miles.

It's been a long time since I've messed with the differentials, but I know they are finicky at times if things aren't done correctly. With that said after ordering my new 4 post lift around 1st of Dec, I got it in and installed, so trying to put it to use and have it pay me back. ;)

Obviously the front cover is straight forward and I did top up the fluid. I just watched a video on a guy replacing pinion seal on the rear diff, obviously should be the same. He painted a line to keep everything....nut, yoke and pinion all lined up. He said to count the exposed threads and replace to that tightness. He counted 4, had the nut marked, and threaded it to where 4 threads were exposed and the nut again lined back up with the pinion and the yoke. Pulling the old seal and pushing the new one in is easy enough, my worry is tightening it back up. Is that the correct method or should it be torqued?

Or do I pay the shop $125 to just take care of it? Again, I bought the lift to make stuff like this easier than laying on the floor, which as I get older makes me want to pay a shop to do it!

FYI....I am really really am wanting the hydraulic jack assembly that mounts into the rail of the 4 post. I'm thinking if I pay myself back enough, I can justify it! Those things are $1000-$1500!!! I won't say what the darn lift cost!
 
I like using a caliper and paint pen to mark exactly where the Pinion nut is... caliper can measure depth...my 18v impact can wiz it off... usually a death match with a flat chisel and a hammer to get the old seal out...big socket or a seal driver to get the new one in...some folks like a touch of permatex... carefully retighten the pinion nut to it's exact spot...maybe a 1/16 to an 1/8 rotation past if you want a little more on the crush washer.

Easy job!

Change your dif fluid while you're at it...folks love the reusable lube locker gaskets. You can check the backlash while you're in there as a double check...

-Mac
 
If there is no play in the pinion and the leak is small I would not worry about it one bit. Next time you change your gear oil you'll rule out the diff cover as the source of the leak. Mine leaked for thousands of miles and I only fixed it when I re-geared. No play, no problem.
 
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Mac,
I like using a caliper and paint pen to mark exactly where the Pinion nut is... caliper can measure depth...my 18v impact can wiz it off... usually a death match with a flat chisel and a hammer to get the old seal out...big socket or a seal driver to get the new one in...some folks like a touch of permatex... carefully retighten the pinion nut to it's exact spot...maybe a 1/16 to an 1/8 rotation past if you want a little more on the crush washer.

Easy job!

Change your dif fluid while you're at it...folks love the reusable lube locker gaskets. You can check the backlash while you're in there as a double check...

-Mac
Thanks for the tip on the reusable seal. Never heard of them before. Ordering one today.
 
Did mine ten thousand miles ago, no problems yet.
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