Leaking Plug on Rear Diff

[GhostStrykre]

I tried googling and searching on this forum, but didn’t see this pop up anywhere for the 5th gen.

Truck is running great, but I was underneath it doing some quick routine inspections when I saw the plug on the rear diff was wet. Doesn’t look awful, but here it is:

and here’s a closer shot:

whatever it is, the leak doesn’t look awful. I was in some snowy conditions and ran the 4WD system a bunch on the snowy roads. Not sure if that’d add to this.

Any concern here? I can try tightening, or maybe this is a good opportunity to drain and replace the fluid (I just hit 60k miles) and swap to the Ford Performance cover lol? Or is everything fine and I’m being an over worried weenie?

Sponsored

 

[ctechbob]

You're being a little over-worried. It is a pipe thread, it is normal to seep a little.

At 60K, now is a good time to change the fluid though. Hit it with some brake cleaner, drain and refill.

 

[9zero1790]

dont look to bad. but it will make you feel better to drain and refill. clean up the cover real well so you can see if its leaking in the future.

 

[Radioman]

As suggested above, I would go ahead and drain and refill after cleaning the area of the plug. I have used Teflon tape or some automotive tread sealant such as:
https://www.amazon.com/Loctite-4836...MI5-Lj75SGgwMVLh-tBh26ZQmBEAQYASABEgJzWvD_BwE

I have used both with great results.

 

[GhostStrykre]

Eeeexcellent info, all! Thanks! Yeah I’ll go for the refill, clean, and monitor. Much appreciated!

 

[GhostStrykre]

You're being a little over-worried. It is a pipe thread, it is normal to seep a little.

At 60K, now is a good time to change the fluid though. Hit it with some brake cleaner, drain and refill.

In prep to attack this assignment I went and watched a few videos on the diffs and transfer case. Interestingly, they all had some weeping around the full bolt like this. Mine appears to look the largest, but I suspect that’s just because I have some extra road grime on the diff cover that absorbed the fluid. Confirms to me what you’re saying, the weep is normal. Really, thanks!

 

[ctechbob]

This is essentially what it is. Lots of manufs have moved on to o-ringed plugs, or gasketed plugs of some kind. Its just old technology that works, just with that one little caveat.

-Edited--

There are scores of trucks in the junkyard that have gone to their death with a pipe thread plug and still have enough oil in them they could probably go another 200,000 miles. It doesn't take much oil to make it look like a big mess.

 

[LawnMM]

Haven't had to do this yet but I'm planning on thread sealer and definitely clean up with brake cleaner when done so you can watch it afterwards

I think you have minimal oil just a lot of grime sticking to it

 

[GhostStrykre]

Yeah, totally agree. The extra road grime made the small amount of oil appear to "bloom" outward on the back of the diff. Makes total sense.

 

[Blmpkn]

Nows a good time to change ALL your drivetrain fluids..

Once you dump that pumpkin.. you're gonna want to.

 

[GhostStrykre]

Nows a good time to change ALL your drivetrain fluids..

Once you dump that pumpkin.. you're gonna want to.

yessir, i've been shopping the materials to do so this morning. it's so easy to do, i might as well do the front and transfer case too. i've seen numerous people on the forums claim this really improved the driving satisfaction too. so ultimately i'm glad i spooked myself into checking on this rear diff.

 

[Canadian Ranger]

Clean the plug and surrounding area with a cloth and some Windex to get rid of the oil. Check it again in a week or so for new oil seeping.

Sponsored