Rear differential fluid leak (1 Viewer)

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Feb 16, 2008
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Was up at windrock park in Tenn yesterday and noticed a leak at the bottom of the rear differential. I topped off the fluid and have been keeping an eye on it all day. I plan on fixing it this week, but was wondering if anyone else has had this happen and if so, what exactly was it.

Thanks.

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07 FJ Cruiser. Appalachia Cruisers. TLCA #22753.
 

Mtbcoach

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Never had it happen on any, will be easier to see once you clean it up. I presume it drives fine, when is the last time you changed the rear differential fluid? Ever have it regeared?

I'd clean it up for up close inspection and hit the threads with some wd40/liquid wrench or the like in case you need to remove/re-torque...
 

BMThiker

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Jordan, I think you probably whacked it enough loosen the seal, and/or some of the nuts have worked loose. I had to re-RTV mine when the first time didn't hold just a few months ago. Kind of a PITA, but no other way to fix it. ATRAC has a way of jarring some of them loose if not properly torqued. You should probably check the nuts on your front diff too.
 
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Thanks guys! Rick, I'm pretty sure that's what happened. The bolts seem to be tight, gonna check then again after work. Talked to a friend, he seems to think it's a seal as well.

I've been checking the fluid constantly, and it's been fine. Just don't want to let this go longer then it needs too. So I'm gonna RTV it sometime this week.

Once again thanks for the help!


07 FJ Cruiser. Appalachia Cruisers. TLCA #22753.
 
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About the only thing it can be is the seal between the third member and the housing. First try to torque down the nuts, but if that doesn't do it you might have to pull off the third member, clean the mating surfaces (hopefully there isn't any significant ding to the housing mating surface), and reinstall with fresh RTV. Just caulking it with RTV as it sits isn't going to work.
 

BMThiker

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I hope my above comment was not interpreted to imply a bead of RTV on the outside would suffice, hence the PITA comment.

To pull the 3rd you will need to drain all fluid, remove the rear sway bar, the elocker motor (and breather line) and wiring harness from the top side. Remove all nuts and washers from the 3rd member. Now start working on the axles...

Remove the rear wheels. You'll have to remove the e-brake cable brackets on each side up to where they cross through the frame (1 on the lower control arm and 1 on the frame of each side). Unplug the wheels sensor and place out of harm's way. Remove/undo the metal clips holding the hard brake lines to the axle housing (more on this below). Remove the 4 hub flange nuts using an open ended wrench. If you use a ratcheting box end wrench you'll get yourself in a real pickle. Carefully slide the axle shaft out of the tube after breaking the hub flange free of the housing. You will be slowly straightening out all the hard brake lines in the process (unless you prefer to just disconnect at the soft/hard connector and rebleed your brakes upon completion). Use a jack stand to rest the end of the axle on (edge of the disc or the outer edge of the hub will work) so that it is not resting on the seal inside the tube. You only need to pull out each side about 4-5 inches to clear the side gears of the 3rd member.

Now get back under the (secured) truck and start pulling the 3rd. A cardboard box stuffed with newspapers makes a good landing pad for this big hunk of steel as you slide it off the guide pins. Now you're ready to start cleaning both surfaces until free of paper or RTV. Since the first time I had to remove my 3rd I've never used the factory paper seals. I just use the black RTV from Toyota and allow it to set up for about 1 hour before I refill the diff with fluild.

The more involved method has you disassemble the entire wheel assembly including the calipers and e-brake drums which is an even bigger PITA. By simply disconnecting the hard lines and carefully stretching them you can circumvent that knuckle busting process. Also with the above method you won't have to disconnect the brake lines or bleed them.
 
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Joined
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Tennessee
Thanks Rick that will help a lot, seeing as this is my first time repairing this! Got Friday off, so were gonna tackle this project then. Thanks again for the help!


07 FJ Cruiser. Appalachia Cruisers. TLCA #22753.
 

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