'95 FJ80 center diff leak -- trying to assess. Please help!

K

kcoub

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Phoenix, AZ
Hello all! I will preface this by saying my dad and I usually work on our FJ80s together... he is my mentor. I am obviously still in training and need help diagnosing what I think should be fairly obvious to the trained eye. I have a '95 FJ80 with 207k miles on it. Bought it at 185k with a maintenance history that was largely unknown, but the truck was in great condition. Kept up with basic maintenance, replaced the radiator and some hoses, etc. In the last couple of weeks I've noticed some fluid leaking from an odd spot on the center differential... seems to be where the electrical connector comes in (see attached photos). Any idea about what this might be (internal O'rings, etc?). This truck only has a locking center diff so I believe it to be a viscous coupler as well which makes me more concerned about the leaking fluid. Any ideas from you experts? Car shifts into 4 Low just fine, no weird noises or major problems when driving in 4L, I just want to get ahead of a major issue. The photos are taken from the drivers side. In the photo with my hand in the picture, you can see the shiny fluid leaking out right above the bolt. The thing I'm holding has play (i.e. I can wiggle it). Yes, I know it's dirtyyyyy. Thanks in advance!
IMG 8776


IMG 8775
 
gummycarbs

gummycarbs

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I believe that there's a rubber o-ring that seals the speedo sensor to the transfer case housing. Pretty sure mine was hardened and leaking.

Your viscous coupler is not leaking.

Oh, and you better start writing FZJ80 or the 1FZ-FE boys will break your kneecaps.
 
LandLocked93

LandLocked93

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I've done it but can't lay hands on the order.
Believe you need this -

edit:looks kinda big, but that's what she said.
 
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LongDuck

LongDuck

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I had a similar leak there and removed the 10mm bolt (*IIRC), which frees up the sensor, then you just pull the assembly out. Since the O-ring is loose, it should just slide out easily. Once out, you can easily see the O-ring that needs to be replaced. I grabbed a generic rubber O-ring from a kit, but Viton would be better, as this is in contact with gear oil, as you can tell. A nice snug fit of the O-ring is preferable, as you insert the speed sender into the output snout. I had to tap mine into place, then reattach the clamp and 10mm bolt. Hasn't leaked since and it's been 5-6 yrs now.

Probably one of the simplest fixes I've done, right up there with changing wiper blades. Good luck,
 
SmokingRocks

SmokingRocks

I bought a Cruiser to keep miles off my Cruiser
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@kcoub download your factory service manual from the link in my signature.
 
jht3

jht3

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Jul 24, 2006
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Fairfax, VA
did this last month. it was just the o-ring on mine. just needed a socket, pick, and rags. only a couple more drops of fluid came out the empty hole

o-ring i got from my local dealer for ~$5. expensive for just an o-ring but i didn't have to spend anytime measuring and putting in the wrong material.

i did pull the other seal out, wiped everything down, and re-assembled. i was worried i should have bought the other seal but so far so good.
 

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