Is my Differential Leaking?

675 Views 14 Replies 6 Participants Last post by SS23, 2 mo ago

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Discussion Starter · 2 mo ago (Edited)

5

Back story: about 40,000km ago and 3-5 years, the rear seal (I think thats what the dealership called it) on the diff was leaking and they replaced it under warranty. (just over 100,000km now). I would have assumed they cleaned it up when they did the job, but honestly i never looked, they found it, and replaced it.

My question. Is this old oil and is there a way to tell? it feels pretty dry and crusty. Around the top of the diff (where all the extra RTV is) it flakes off.
Is this concerning and should it be fixed, or only a slow leak?
Is there a way for me to leave it and check to see if it "gets worse"?
I noticed this only because I was swapping out my diff fluids and it actually looks brand new and quite full. Not quite seeping out, but at the limit. Its never left a spot on my garage floor. The fluid was replaced last 2 years ago ~10,000km ago. (i dont use this vehicle to commute to work so it sits a lot).
Is it possible the diff breather mod/relocation is the issue? I did that about 500km ago (3 months or so)

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Please dont judge the rust. it looks so bad with this lighting and my camera.

Bonus question. If I loosened the drain plug, can I just put a bit more black permatex oil gasket on the plug and thread it in? (~20ft/lbs)

Appreciate any insight. Thanks.

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87iroc

· #2 · 2 mo ago

Your pinion seal does appear to be leaking. I'd clean it up and see if it comes back. Drain plug shouldn't need permatex. I'd give it a little extra 'umpf' to tighten it. Give it a light tug and see if its a bit loose. YOu could also find the torque spec.

If it was leaking bad it'd be super damp and dripping. Dust will act as oil dry and dry out a leak if its minor and make it look like that.

Also, hows your diff breather? Have you had it underwater or done a wter crossing if you haven't put an extension on it? First sign you have water in diff is axle seals blowing out(not the two you show)

I think I'd do a drain/fill on your diff fluid. Make sure your breather is working(if you haven't done an extension, I would. Its 30-40 bucks). I'd then clean it up and see what it looks like in 3 months.

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SS23

· #3 · 2 mo ago

87iroc said:
Drain plug shouldn't need permatex

Mine has always needed rtv, for what it's worth. It's easy enough.
Looks like you're going to need a cover gasket and a pinion seal too.

www.z1offroad.com

OEM Frontier / Xterra Rear Differential Pinion Seal - Z1 Off-Road - Performance OEM and Aftermarket Engineered Parts Global Leader Nissan Truck & SUV

www.z1offroad.com

www.z1offroad.com

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SS23

· #4 · 2 mo ago

87iroc said:
Also, hows your diff breather? Have you had it underwater or done a wter crossing if you haven't put an extension on it? First sign you have water in diff is axle seals blowing out(not the two you show)

This is good advice

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Discussion Starter · #5 · 2 mo ago (Edited)

2

87iroc said:
Your pinion seal does appear to be leaking. I'd clean it up and see if it comes back. Drain plug shouldn't need permatex. I'd give it a little extra 'umpf' to tighten it. Give it a light tug and see if its a bit loose. YOu could also find the torque spec.

If it was leaking bad it'd be super damp and dripping. Dust will act as oil dry and dry out a leak if its minor and make it look like that.

Also, hows your diff breather? Have you had it underwater or done a wter crossing if you haven't put an extension on it? First sign you have water in diff is axle seals blowing out(not the two you show)

I think I'd do a drain/fill on your diff fluid. Make sure your breather is working(if you haven't done an extension, I would. Its 30-40 bucks). I'd then clean it up and see what it looks like in 3 months.

Pinion seal! I think thats what they replaced and called it the read diff seal. Doesn't bode well if its been replaced once, and needs it again... The torque spec I found was
Rear Differential Fill Plug (M226) (with or without Locker): 25 ft-lbs (Apply Silicon RTV or Equal)
Rear Differential Drain Plug (M226) (with or without Locker): 20 ft-lbs (Apply Silicon RTV or Equal)

I actually just did the diff breather mod (about 3 months ago ~500km). You can just see it in one of hte pictures. I'm sure its been close to being submerged with how some of the roads can be, but I've never taken it through a creek/water crossing. I'll take a look around the brakes to see if anything is leaking out the axel, but I didn't see anything last night.

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I'm going to clean it up (Brake cleaner?) and see how it goes. It also looks like it leaking around hte top left of the diff too. I dont think I'll replace the diff fluid. it looks brand new and was replaced 10k km ago.

(ignore the crud on the paper towel, its not from inside the diff. This was taken from inside the diff by sticking my finger in the fill port)

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Discussion Starter · #6 · 2 mo ago

SS23 said:
Mine has always needed rtv, for what it's worth. It's easy enough.
Looks like you're going to need a cover gasket and a pinion seal too.

OEM Frontier / Xterra Rear Differential Pinion Seal - Z1 Off-Road - Performance OEM and Aftermarket Engineered Parts Global Leader Nissan Truck & SUV

www.z1offroad.com

Does the cover have a gasket or is it just RTV? There is a lot of RTV that oozed out the top.

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FYI for anyone, the pictures are full res if you right click on them and "view image" for the pictures in the original post.

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87iroc

· #7 · 2 mo ago

There is no gasket from the factory. I runa 'lube locker' gasket on mine now as the RTV is a pain.

I'd clean it up with brake clean and see what happens.

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Ssanders224

· #8 · 2 mo ago

87iroc said:
Drain plug shouldn't need permatex. I'd give it a little extra 'umpf' to tighten it. Give it a light tug and see if its a bit loose.

M226 drain and fill plugs definitely DO need RTV.
(Per FSM)

87iroc said:
I'd clean it up with brake clean and see what happens.

This.
Ultimately, you probably need a new pinion seal, but it may be seeping so slowly that you can put it off for a little while.

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Discussion Starter · #9 · 2 mo ago

Ssanders224 said:
Ultimately, you probably need a new pinion seal, but it may be seeping so slowly that you can put it off for a little while.

Does it also look like its leaking around the differential cover at the top left or maybe thats from the pinion seal (doubtful I think)? I suppose the course of action would be to monitor the cover and replace the RTV when changing the fluid next time(30,000km from now)

Also, If I loosened the drain plug, can I just put a bit more black permatex oil gasket on the plug and tighten it up? (~20ft/lbs) or do I need to remove, clean, RTV, and tighten?

thanks.,

87iroc

· #10 · 2 mo ago

Huh. Maybe that’s why my plugs leak. You shouldn’t need it but I’ll be sure to add a bit in future.
That said. OP. if you add it be sure to get as much oil out of internal threads as possible.

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Just a Hunter

· #11 · 2 mo ago

Permatex Gear Oil RTV gasket maker is my choice for differential gaskets and thread sealing.

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early 2010

· #12 · 2 mo ago

Weep, lightly. But those are far from a leak. The amount of oil that has come out of that differential and wetted the surfaces is only a couple milliliters. Barely more than a few drops. Undetectable in checking the oil level.

Leave it alone. Trying to fix that now is just a lot of work without gains. Didn't say ignore it. In another 30-100k miles it may actually get bad enough to turn into a leak.

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Just a Hunter

· #13 · 2 mo ago

Where did all the oil come from as seen on the picture of your gloved hand?

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Discussion Starter · #14 · 2 mo ago

Just a Hunter said:
Where did all the oil come from as seen on the picture of your gloved hand?

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This is the oil in the rear differential that I took by sticking my finger in the fill hole. I can see the confusion. Poorly explained on my part.
The oil where I think its leaking is completely dry and nothing comes off but dirt and grime when i wipe it. I've cleaned up both areas with some brake cleaner and I'll keep an eye on it as most have mentioned.

Thanks again everyone. I appreicate the conversation, help, and ideas.

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SS23

· #15 · 2 mo ago

secular said:
Does the cover have a gasket or is it just RTV? There is a lot of RTV that oozed out the top.
View attachment 150134

FYI for anyone, the pictures are full res if you right click on them and "view image" for the pictures in the original post.

The cheapest way to seal the cover is to get a paper gasket, spread rtv evenly on both sides and stick it on a clean prepped surface. If you do a good job prepping the surface, that will last a hundred thousand miles or more. The more expensive route is to get a lubelocker gasket as mentioned. You shouldn't have rtv oozing everywhere, nor just rtv in place of your gasket.

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