RTH: Rear Differential Gushing Oil

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Joined
Nov 16, 2013
Threads
43
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410
Location
Connecticut
Ok, I know my rig has rust on it. But I take care of her and do all PM and drive her.

Checked the rear differential this past weekend and it needed some oil. I drained it (very minute amount of residue on the plug and fluid looked ok) and filled it.

Three days later I walk out and see this...
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Obviously it's more like hemorrhaging oil from the back.

It's not dripping straight down though. It's all on the axle and above the axle and the undercarriage. I know the pictures suck but hopefully you can see what I am talking about.

It's a 1998 with 180k miles and other than the rust, she runs great.

Any ideas???
 
Looks like it's all downwind of the very front of the diff. If so, pinion seal? Maybe cuz it wasn't full enough before to spill it?
 
I'm with @e9999. It looks like there was not enough fluid in there to spill and once you refilled it leaked out of the pinion seal and sprayed back when you were driving.
 
The issue is that the seal is behind a large castle nut which sets your pinion preload for the gears. If you loosen it, you will lose the set preload. On my previous 80, I removed the nut, took the pinion flange off and replaced the seal and put the nut back on but tightened it about 1/8" further to estimate the pinion depth and had no issues.

You can alleviate this issue in the future by installing a solid spacer instead of the stock pinion crush washer that is installed but that would require tearing the 3rd member apart. If you have no gears, lockers to install then I would replace the seal and tighten the nut just a bit further to take the slack up.
 
If it's a Land Cruiser part you need, @beno is the man.
 
How much oil was removed and how much oil was replaced?

My gut says overfilled and puking out the vent, running down to the pinion and being slung all over... also cheaper and easier place to start.

If you effectively have been running with no pinion seal and the oil was super low, just sealing and re-filling may not fix it, if it's been running low for a long time internal damage could have been done.
 
Ok so a bit more information and some more pictures in case it helps.

When I opened the fill plug, I would say it was half full of oil. I filled it until it was slowly oozing from the fill hole.

I noticed when I first got the rig that it was running low, but not nothing, in there.

Could this be caused by a plugged breather?
 
What about cleaning it, get it dry and going for a short drive and see where the fluid is coming from. That is quite the oil slick you have going on.
 
Exxon Valdez... At least it's not your engine...
 
Well, look on the bright side. The rear of your undercarriage has had copious amounts of rust prevention applied. No WD40 needed when modding in the future.
 
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