Rear Diff Leak

[PWD4R]

I searched around and I mainly found ones of the diff breather leaking or being clogged or the fill plug was leaking after a recent change. I don't think those apply to me so here's what I have and the quick story.

I got my diff fluid changed about two months ago and I check it weekly to make sure it's all good. Always dry on the outside even after off roading. Went out 2 weeks ago on Sunday and I got hung up on my rear diff once (guy referred to it as a third member but I am not 100% on what the third member is)
I noticed some rock chalk on my drain plug from the diff and all was dry up until today when I noticed. I know it was dry over the weekend (I haven't driven it since Sunday) so sometime between then and now the leak started. What do I need to do to fix it

Thank you all


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[st8rocks]

Rinse the area in brake clean to see where the leak is coming from. Are you sure the person that changed your diff fluid replaced the drain plug metal gasket? It's a serviceable part and offend overlooked.

 

[PWD4R]

Rinse the area in brake clean to see where the leak is coming from. Are you sure the person that changed your diff fluid replaced the drain plug metal gasket? It's a serviceable part and offend overlooked.

It was 100% clear before this (meaning no dried oil anywhere) and I am kind of convinced they may not have even changed the fluid. I will change it this weekend. I touched the oil and it came off looking like dirty water and felt thinner than I remember (then again I haven't touched it in 2 years or so)

I am going to the parts department tomorrow to pick up my LBJs and radiator so I will see about getting that too.


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[Coffey50]

I know its silly, but do you have the washer that goes with the drain bolt ?

 

[mckennar]

I strongly suggest you clean the area off per [MENTION=109391]st8rocks[/MENTION] suggestion.

Clean all of that debris away from the plug head, then put a socket / torque wrench on it to ensure it's where it needs to be.

There's a possibility it was loosened a tiny bit by the impact.

 

[techno]

BTW, this part of the rear axle/differential is the 3rd member, so your leak is probably not related to your offroad adventure.

 

[BoomSticks]

I strongly suggest you clean the area off per [MENTION=109391]st8rocks[/MENTION] suggestion.

Clean all of that debris away from the plug head, then put a socket / torque wrench on it to ensure it's where it needs to be.

Possibility it was loosened a tiny bit by the impact.

This. Start here.

When troubleshooting, first verify presence or absence of normal specs and functioning.

Don't assume it's working right or where/how you left it until you verify, especially when it's attached to a 5000lb rattling, bouncing, vibrating, dirty metal box.

 

[PWD4R]

I strongly suggest you clean the area off per [MENTION=109391]st8rocks[/MENTION] suggestion.

Clean all of that debris away from the plug head, then put a socket / torque wrench on it to ensure it's where it needs to be.

There's a possibility it was loosened a tiny bit by the impact.

Forgot to update but I feel dumb. It was so covered in tiny rocks and dirt and the drain plug was loose. A quarter turn and it would have fallen out. Good thing it was an inexpensive fix (I still bought diff fluid and a new crush washer and changed it)


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[mckennar]

Forgot to update but I feel dumb. It was so covered in tiny rocks and dirt and the drain plug was loose. A quarter turn and it would have fallen out. Good thing it was an inexpensive fix (I still bought diff fluid and a new crush washer and changed it)


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Glad it was a cheap fix! But so often the line between catastrophe (i.e. rear end failure on the road due to no fluid) and safe motoring is a few turns of a drain plug. Glad you found it and saved your rear end (literally/figuratively).

 

[PWD4R]

Glad it was a cheap fix! But so often the line between catastrophe (i.e. rear end failure on the road due to no fluid) and safe motoring is a few turns of a drain plug. Glad you found it and saved your rear end (literally/figuratively).

Exactly. I expected the worst ha. It took a few minutes to clean out the area around the plug. I put valvoline synthetic in there... i hope that's a good kind. It was pricey


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[mckennar]

I put valvoline synthetic in there... i hope that's a good kind. It was pricey.

In my somewhat limited experience, it's more about the weight/type of gear oil than it is about the brand name. From the FSM, the rear end should be 80w-90 API GL-5 hypoid gear oil. I realize there's a TSB that covers '03+ and indicates 75w-85 full synthetic. Not sure if it calls for that on our runners.

I'm sure there are anecdotes for days on either side of that (75w-80, synth, no synth etc), but 80w-90 is what I've used in the past whenever I potentially ingested water into my rear diff before breather relocation (water crossings, local low-water floods, etc) and "so far so good." As far as a brand, I bought a case of Mobil HD Plus 80w-90 a few years ago and have barely put a dent in it between three 4Runners, an RX-8 and two Subarus.

 

[PWD4R]

In my somewhat limited experience, it's more about the weight/type of gear oil than it is about the brand name. From the FSM, the rear end should be 80w-90 API GL-5 hypoid gear oil. I realize there's a TSB that covers '03+ and indicates 75w-85 full synthetic. Not sure if it calls for that on our runners.



I'm sure there are anecdotes for days on either side of that (75w-80, synth, no synth etc), but 80w-90 is what I've used in the past whenever I potentially ingested water into my rear diff before breather relocation (water crossings, local low-water floods, etc) and "so far so good." As far as a brand, I bought a case of Mobil HD Plus 80w-90 a few years ago and have barely put a dent in it between three 4Runners, an RX-8 and two Subarus.

I did 75W-90 based on what I have seen here because that's what goes in front diff and xfer case so people just do it to all 3


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