Rear Differential Drain Plug Not At Bottom

Getting ready to change the gear lube on my differentials this weekend with Amsoil Synthetic. I noticed that the rear drain plug is at the 6 o'clock position, but more like 5 o'clock. Doesn't this prevent all the fluid from draining out?

Should I back the left rear tire up on a couple of boards, or a ramp before I drain it?

 

That's actually a clever idea!
I think they offset the plug a bit so that it isn't the lowest point between he rear end and the ground. Better to bottom out on the housing than on the plug.

 

I pull the plug and jack up the side the drain's on first to drain any oil in the axle tube. Once it's drained for a few minutes i drop it and raise the other side moving the drain towards 6 o'clock and let it finish draining.

 

Do you place a floor jack under the axle to jack it up? I don't have one. I just do it in my driveway....

 

Unless I'm misunderstanding you, there are inner axle seals so that oil does not go into the axle tube. No reason to drain the axles.

 

+1, no diff oil in there. You have greased bearings but no oil.

 

Oh thank God. One less thing to obsess about....But what about my obsession with the drain plug being at the 5 o'clock position? Should I not worry about it?

 

Don't worry about it.

 

There is no inner seal in the axle tubes.

The differential gear oil does go down the axle tubes. The Gasket seals are only at the end of the tube.

If you look at where the Fill Plug is located, and you fill to that level the oil will have to go down the tube.
The above axle damage started out as a very small pinion seal leak. Most rear differentials hold about two to three quarts of lubricant. This heavy oil lubricates the gears and a small amount runs down the axle tubes to lubricate the axle bearings.

 

My bad, learned something today, thanks.

 

I don't have a floor jack, so I may just go to Advance Auto Parts and buy some of their house-brand gear lube, and run it for a few miles and drain it.

I guess I could always deflate one tire. Then re-inflate it, and deflate the other....

On second thought, I stopped caring...

 

Actually, in looking at the drawing, won't there be a siphoning, or capillary effect, that will draw the small amount of fluid out of the axle?

 

How does a poor suburban boy "tilt the axle"????

 

This. There would be so little left it wouldn't make a spit of difference.

 

Don't over think this. Just drain and refill and you will not have any issues. Trust me I've been doing this for many years.

 

And you got the magnet in the drain plug to pick up little metal bits too.

 

Your truck did come with a jack right, that's all you need to lift one side.

 

I believe that the thickness of the housing mostly cancels that out. So, yes it's offset, but if you take into account the thickness of the housing, it's probably pretty close to level there. Often there is also a small depression milled in, that allows drainage towards the hole. I have not had the axle open to verify, but I've seen it in other axles.

 

Your not going to get all the oil out of the diff. There are small baffles in the low point. Only way to get it all is to pull the guts and wipe it out with a rag. I wouldnt worry about the small amount left in the bottom.

 

Yeah, any shavings left behind is such a small amount it's a non issue. If it gets picked back up off the bottom of the diff, then that's what the magnet is for. There isn't enough old oil left behind to contaminate the new, so that's not a problem either. Just change it the way your supposed to, at the right times and it will live a long life.