Rear Diff fluid amount

[coupecustom]

This weekend I tackled changing the fluid in the rear end. The previous owner noted to me that it needed to be changed when I bought the truck a couple years ago, and I'm finally getting around to do it. The motivation was simply because the cover was wet and greasy and I could tell it must have a bit of a leak.

Yesterday I drained the fluid, which about 3.5 quarts came out. I was a bit surprised, but I moved on and got the cover cleaned up and old paper gasket off. I used some RTV and sealed it back up. From what I have read the rear should take 2 quarts of fluid. I have now put 4 quarts in and I'm not to the 3/8 mark below the fill hole. The truck is level.

So anybody have any ideas what is going on? :dunno:

 

[TYRODD]

Re: Rear Diff fluid amount

I generally fill the rear end until it reaches the plug. That is not a stock cover so it may hold more fluid.

 

[coupecustom]

Re: Rear Diff fluid amount

It just seems like so much oil. I'm gonna put another quart in or till I can feel it with my finger. What's the worst that could happen anyway?

 

[intheclouds1977]

Re: Rear Diff fluid amount

The fill port is on the front side of the differential on the passenger side, a few inches behind the yoke. It takes a 3/8" ratchet to remove. The port in that aftermarket diff cover is too high.

Overfilling will likely result in excess oil coming out the breather tube or could blow the seal on the cover if there's not enough room for expansion.

 

[atkonkler]

Re: Rear Diff fluid amount

Plug that hole....on the cover...and use the fill plug to fill it....imo

 

[wheels]

Re: Rear Diff fluid amount

Yeah use the stock fill plug on the front

 

[coupecustom]

Re: Rear Diff fluid amount

Thank you, I found the stock fill plug. I also found out why the previous owner probably installed the new cover. The fill hole plug was completely stripped so I couldn't fit anything in there that would get it out. I presume it used to be a square hole that you could put an extension on your ratchet and then undo it. Mine must have been tightened so tight at one point that the next time someone tried to undo it, it stripped out the inside. I think the only thing I could do now is remove the rear end and then probably drill a hole through the plug and try my hand at an easy out. What a pain in the a$$
I'm not surprised, po over tightened so many things on the truck that I've spent a lot of time drilling an re-tapping. :rant:

So, I guess I could just remove some, but it now becomes how much. I have a total of 5 quarts in there....ya "5". I just filled it to where I could put my finger in the fill hole on the cover and feel the oil.

 

[intheclouds1977]

Re: Rear Diff fluid amount

Measure how far below the diff cover hole the actual fill port is. Use a feeler gauge down into the diff through the cover fill hole so you know when it's filled to the right level. Basically...if the true fill port is 3" lower (measure to figure out), then stick a piece of wire 3" down into the cover port and see if it touches oit. Add until oil barely reaches the wire. Remember, the fill line is the BOTTOM of the stock fill port.

Hopefully the easy out works for you when you get around to it...ugh.

 

[Static]

Re: Rear Diff fluid amount

If you put 5 quarts in take 3 quarts out and you should be good to go

 

[coupecustom]

Re: Rear Diff fluid amount

Measure how far below the diff cover hole the actual fill port is. Use a feeler gauge down into the diff through the cover fill hole so you know when it's filled to the right level. Basically...if the true fill port is 3" lower (measure to figure out), then stick a piece of wire 3" down into the cover port and see if it touches oit. Add until oil barely reaches the wire. Remember, the fill line is the BOTTOM of the stock fill port.

Well, I tried this...I just really couldn't get accurate enough. I had a really hard time measuring with the wire and even getting to know what would be level and the difference with the cover fill plug.

I ended up just removing 2.7 ish quarts. I just filled my bottles back up....there's a window so I could tell what was a full quart compared to another unopened bottle. Basically that leaves me 2.2-2.3 quarts in the rear end. I think I'm going to leave it at that for right now.

Now my questions is, what is the disadvantage of running it too low. I assume it would ruin the limited slip eventually?

 

[mattw]

Re: Rear Diff fluid amount

The fill hole plug was completely stripped so I couldn't fit anything in there that would get it out. I presume it used to be a square hole that you could put an extension on your ratchet and then undo it. Mine must have been tightened so tight at one point that the next time someone tried to undo it, it stripped out the inside. I think the only thing I could do now is remove the rear end and then probably drill a hole through the plug and try my hand at an easy out. What a pain in the a$$

I've welded a bolt to the stock plug before and removed them that way.. The heat from the weld usually makes them much easier to get out and the bolt you welded to it gives you something to turn..

 

[Norm]

Re: Rear Diff fluid amount

Find a old chisel that is pretty close to the size of the squar hole. Beat it in and use some vise grips and try to extract it. You should have to take of the rear cover unless you have a leak from it.

 

[Don W.]

Re: Rear Diff fluid amount

Woe Nelly. Take that cover off and turn it over. I'll bet that puts the fill hole you have your hose in at very close to the correct level. Please don't run it with oil anywhere close to that fill plug where it is now. You will you wish you never did. Once turned over IF the fill hole on the cover is too low by a small amount, say 3/8 or less then run it. Much lower that than put a street ell on the hole which will allow you to raise the fill level to the top of the hole or even a bit higher if you want. Simple.

Also what the heck is that rubber thingie with the brass colored center in the cover?

 

[coupecustom]

Re: Rear Diff fluid amount

Also what the heck is that rubber thingie with the brass colored center in the cover?

Welp, I'm not going to flip it around now. I've already sealed it with RTV. The black thing is useless really. I think its there to protect the brass drain plug since it sticks out a bit. I think running a hair over 2 quarts will be fine for now. I don't think it will ruin any thing.

I've welded a bolt to the stock plug before and removed them that way.. The heat from the weld usually makes them much easier to get out and the bolt you welded to it gives you something to turn..

Nice, love this idea. Can't believe the thing is that stuck that it got stripped out.