2014 Rear diff leaking around fill plug

TLDR: Rear diff leaking around fill plug. I have replaced the fill plug, replaced the crush washer(twice), and verified that the breather thing is mobile. Should i seal it? if so what with?

Hello All

My 14 limited 4wd has minor oil leak around the fill plug. I dont have any good measurements on how much its loosing but every time i park there is thin a trail of oil and a couple drops hanging in surface tension off the bottom. This is very likely my fault because I'm a stupid noob who over tightened the fill plug till it spun freely a while back. At the time I had the dealer extract the plug and they said my diff was good but i dont think so anymore.

While troubleshooting i read a bunch of forum posts and followed the advice. Replaced the fill plug, replaced the crush washer(twice), and verified that the breather thingy is mobile. At this point im fairly certain that the diff housing is damaged. Im tempted to ignore it but i live in Appalachia and even the on-road stuff in my area has some steep grade to it and thats ignoring the off-road stuff i purchased this truck to do. This issue makes me too nervous to ignore.

I dont have the thousands to replace the axle housing and it will be a few months before i can afford the hundreds it would cost for a shop to do a fix action. I dont like the idea of solutions that make the plug semi permanent with sealant/glue but i suspect im out of alternatives. What are your thoughts?

Many thanks in advance to those add their two cents.

 

Maybe a dumb question, but doesn't diff fluid coming out of the fill plug mean the diff is overfilled? The drain plug leaking would be a different story...

 

Condolences on the thread. I’ve been really close to making similar mistakes, so no smart ass comments from me lol. If it spun, then I think it’s never gonna seal right.

I would hope that installing a thread insert is a possibility. Not sure if the access will allow for drilling out and rethreading the hole in place, or if removal of the axle is necessary. It might make more sense to remove the axle though. Either way, I imagine it would have to be done with the third member removed, just so you can make sure you can get all the metal chips from getting in the works.

Not sure if there are any epoxy-type products out there that would do a good job repairing threads, but if there are, that might be an easier possibility.

Given the age of the vehicle, it might not be a bad time to go through the entire axle to see if it needs any seals or bearings. Might as well replace any rubber bushings etc.

 

I’ve seen a video of an axle with a transparent housings, made so you can see how the fluid moves at speed. It’s like when you are making a fruit smoothie or using a food processor. Nothing stays at the bottom when things are turning, so I’m sure the back end of the fill plug is constantly being washed with oil at fairly high pressure.

It was an interesting video, made to show that not all aftermarket axle/pumpkin housings are created equal, because an incorrect shape would completely alter the flow path of the fluid, causing increased fluid temps, failures etc.

 

When vehicle is moving the fluid is not stationary.

 

^Funny timing

 

You might want to contact ECGS:

https://eastcoastgearsupply.com/

They deal with differentials all day long, and they may have a solution for you. They must have come across this before.

 

That was the one!

 

I didnt even know they existed. Thats a great resource. I will shoot them an email and see what they say. Thankyou.

having a drill & tap done on the housing was my first thought. Spoke with the toyota rep who said it would be virtually impossible to get the gears clean of metal shavings afterwords. This is the only time in my life i wished i purchased a ford. They can just replace the cover. It is probably time to go through and replace seals, bearings, and bushings across the whole vehicle. I just need the time and money to do so. Hopefully i will have the time and money next summer.

 

I hear that! It might be worth considering finding a salvage axle. Sometimes you can get lucky! I found a transfer case for my 4runnner with 50k miles on it. Brand new woukd have been close to $3k. I paid less than 200 bucks!

A salvage axle housing (or the entire thing with third member) would allow you to rebuild it on the bench, at your leisure, as budget allows. It sounds like complete overkill for a stripped thread, but it may make the most practical and financial sense in this situation.

 

How do the threads look?
Does the plug now tighten down properly?

 

Spoke to ECGS. They recommended RTV silicon sealant as a bandaid. Turns out companies make a type of the stuff specifically for sealing up diffs. Permatex 81182. $12 on Amazon.

As a proper fix they recommend either cutting out and welding in a new bung or replacing the axle housing with used/salvage.

 

Damn! that's a good deal. now that im a novice car guy, i really should start learning how to use salvage yards to my advantage.

 

Sorry for your troubles. Hopefully, others will see this thread before overtightening their fill plug...

 

Are you able to torque the new plug or spec, or does it spin loosely as well?

 

I have always used TEFLON sealant on fill plugs I have never had an issue.

https://www.autozone.com/sealants-g...MEu36CNX8XQ8saK8mKBoCEXEQAvD_BwE&gclsrc=aw.ds

 

Once i got the old one out the new ones no longer spin freely. Yes i am able to get it torqued to spec, 36 foot lbs.

 

I personally would not replace the entire housing on this. I would wrap the threads with teflon tape or similar in order to get a good seal. I would also, after that, clean the area really well and apply some rtv sealant. This is a low pressure leak so it should stop after doing this.

 

Thats the plan for now though i hadnt considered teflon tape around the threads (didnt know thats a thing). I ordered the RTV and ill swing out to pick up some teflon tape tomorrow when i buy the brake cleaner. Replacing the housing is up in the air for when i replace bearings & bushings and such depending on cost. But my wallet is informing me that the answer to that question is months away.

 

Interesting. The plug has straight thread (as opposed to pipe thread) which doesn't seal. The crush washer does the sealing. Are you using an OEM crush washer (rounded profile, flattened when torqued down)?

 

Yep, its an OEM crush washer. Got it from the dealer. My initial attempts to extract the stripped plug were very brief but also hamfisted so i cant rule that out as the cause. The diff bung LOOKS fine, even to the eyes of the yota mech who told me so but lo and behold, its leaking. I suspect the mating surface on the bung to have some kind of inconspicuous damage. I can post a pic tomorrow when i go to seal it.

 

OH! I just realized im gonna have to buy a new crush washer. Anybody got the PN for that handy? If not i can easily find out tomorrow.

 

My receipt says:

12157-10010: Gasket, Drain Plug

Same part for front and rear fill ports.

 

Awesome! Much appreciated man.

 

Since you are able to torque to spec, a new washer and a sealer is the way to go, as long as the sealer is made to work with oil and heat. I would do the minimum required to stop the leak. If it works, leave that salvage axle housing for the next poor schmuck lol.