Found a cap under my charger, what is it for?

[acelondon]

74SE-318-727-3.23suregrip

im no loosing any fluids that i can tell, but i havent started the car for fear of killing my poor sick little 318.
picture attached

another question.

I think my rear end is empty, because it leaks all over its self, and i get a grinding noise when making tight turns.
how hard is it to give it a new gasket and refill it. I have a floor jack(2ton), 2 jack stands(2 ton each), and 2wheel ramps(4 ton each)

[flyinlow]

Dont recognise the cap. Looks kind of like the temporary rubber freeze plugs used for repairs ,but if that had popped out you would have lost all your coolant.
what axle size do you have?  81/4 gasket is simple, 83/4 you have to pull the axles first then remove the carrier to change the gasket. If rear end is making noise you might want to check  gears/sure grip unit.

[terrible one]

Dude if you've been driving on that rear with no fluid and you're hearing a grinding noise now you can probably expect your gears to be shot.

[hutch]

i use plugs like that when I put a tranny on the shelf.  I slap in in the hole where the dipstick goes.  its just a standard plug.

you can pop out the plug on your rear end and stick your finger down the hole and see what gear oil you have if any.  but the best thing to do is pop off that rear plate and take a look at any metal you might have in your oil.   thats an easy job to take a peek and replace the gasket.

[craigandlynda]

i feel like i've seen that cap before...is it hollow underneath, and not painted inside the hollow spot?

[mally69]

We have a cap just like that except it is a plug for the round flat tub that catches the oil during an oil change.

[rt green]

noise on turns only? quiet when striaght? axle bearing going out.

[375instroke]

Gear oil could have leaked onto the axle bearings and washed the grease out of them, causing the noise.

[mikepmcs]

We have a cap just like that except it is a plug for the round flat tub that catches the oil during an oil change.

That's exactly what I thought when I saw it too.  Oil drain pan plug.