Front diff leaking from drain plug

I first noticed it around two weeks after changing my differential fluid on April 21. I could see the new crush washer and guessed that some debris might be preventing a proper seal. The next day I drained the fluid cleaned all around the drain area then re filled the differential. Kept the same crush washer as it has only been a month since I put it on. Last night I noticed it still is leaking despite the drain plug being on there real tight.

I don't think it's the axle seal as the fluid is only coming from around the drain plug. What do y'all think? How about putting some white tape on the threads of the drain plug or is there such a thing as a bad crush washer?

 

Yea. I would drain and clean it really good and try some Teflon tape on the threads. It could be that simple.

 

Crush washer are intended to be single use items. They are cheap enough to install new each time. Although Ive reused them with good results.

 

I did replace it when I did the change on April 21. The leak began. I'm going to now drain and fill for a second time but this time with teflon around the threads. How annoying.

 

You used the correct washer; part number

$7 90430-24003 Front Differential Drain Plug Gasket

90430-24003?

 

Did you torque to spec?

 

Use a new washer this time.
Yes, you might get away with multiple, or even many uses of one washer but as mentioned that's not what was intended.

If teflon tape and a new washer doesn't work, you have other problems.

 

There's also a proper orientation of the crush washer. You'll notice one side is flat and the other more rounded. Flat side goes towards the plug.

I personally don't torque drain plugs. Dry and wet are two different torque specs so it'd be easy to overtighten it. I just go by feel and get it nice and snug.

 

If you use Teflon tape your torque spec will be off as the slippery tape will change the characteristics of the torquing. You also run the risk of a piece of the tape breaking off and getting into the diff and fouling a seal somewhere else in the assembly.

If Teflon tape was needed, there would be oil all over the road, as 99.9999% of cars do not require it for a proper seal on their diffs, trannies, or oil pans. Get a new crush washer, clean the plug and the mating surface, and torque to spec either with a wrench or by feel.

Just my advice.

 

I have done my diff fluid twice and used the same washer twice without issue.

Are you sure it’s leaking or is it just residual oil left from changing the oil?

I thought I had a leaking CV seal once after a change and it was just residual oil.

Place a blank piece of paper under the diff overnight and see how the paper looks.

A true leak is 5 drops a minute.

 

^X2

While I have used, and don't see a problem with careful use of PTFE, it should't, well, it isn't necessary.

I'm with @EatSleepTacos on the use of a torque wrench on crush washers, and even drain bolts in general. I have, and regularly use a couple of spendy torque wrenches, but I did a lot more damage than good with cheap ones the first 30 years of my life.

 

Yes.

I actually thought that to be a possibility. I will compare and take a closer at the crush washer when I get a new one tomorrow from the dealer to drain and fill for the second time. The fill plug crush washer is easy to identify in which orientation it goes in as it has a "v" shape. The drain plug washer is a copper "normal" looking washer.

I don't think residual oil would still continue to drop two weeks after the change. I wiped down the entire front diff to clean it the first time I noticed it. The next day again everything beneath the drain plug was covered in diff oil.

Yes I did. 48 lb-ft.

 

Oh yeah I forgot it’s the copper one. As far as I know there’s no correct orientation for that one.

 

Well that throws that idea out the window. However I just remembered when I took a closer look at the washer it had some imperfections. Little tiny spikes on the washer, would that be enough to prevent a tight seal? Either way I shall drain and refill with a new crusher after cleaning the entire area around the drain plug enough to make it shine.

 

Brake cleaner will do a great job at getting it all off. Just try not to spray it on the cv boot. I don’t think it’s kind to rubber

 

I know it's recommended to replace the crush washer everytime but I haven't ever replaced one and I've never had any leaks.

My taco has 135k miles. so 27 oil changes. I have done the rear diff 13 times. long story, but arb air lockers suck and I have had 4 different 3rd members in the last year all with gear breakin done.

 

I don’t think I would use Teflon tape. Some drain plugs I’ve encountered have been nerve-racking enough to remove.

I use a torque wrench to crush the washer (hopefully) properly.

If I were in your situation, I would clean the area spotless, and put a torque wrench on it again. Maybe put a schooch more in to see if it stops leaking. If not, then drain and try again.

 

Yeah I'm reconsidering now that I'm seeing everything you guys are telling me. That's my next course of action in hopes of stopping the annoying leak. I will report back in order to have the information for future reference in case anyone else experiences the same problem.

 

No more dripping and finally good to go.

Nearly 5 months later I finally drained and re filled my front diff two days ago. I was .2 quarts low as the leak persisted throughout the 5 months. Swapped out both crush washers as always.
What I did different this time was get a torque wrench and properly torque to the spec of 48 ft-lbs. for the drain plug. I did not realize how tough it was to apply 48 ft-lbs of force under the truck haha! That fixed it. So the error the previous times was not torquing to spec. This just reinforces how important torque wrenches are.