Replacing Rear Diff Fluid

[Eaglekeeper61]

I don't care who you are that's funny right there!!!

Gwad, I love it.... The handy dandy special 4 sided wrench!!!

 

[ej76623]

We had to put close to 400 ft/lb of torque on my bottom drain plug to get it out.

You're not kidding about that, i used a breaker bar, and 1foot/torque (my right foot)

I used the mobil1 75w140, made the humming leprechaun a little better.

Any suggestions if i should put an additive? Any recommendations? Thanks.

 

[EXPLORER04]

The fill plug takes 3/8" as pictured. The drain plug is 1". You can use a 1" to 3/4" adapter on 1/2" drive.

Where can i find the 1" adapter??

 

[XCAMP]

I got my adapter at sears. They aren't easy to find. I went to home depot, the local hardware store and was about to just order one online.

I have changed my fluid a few times now and I can't tell that the modifier is making any difference to the whining. I have tried both adding almost a full tube of the stuff from advanced auto, to last time only doing the recommended amount. I don't think it makes a difference.

 

[jasongt06]

Here is what you need, Harbor Freight #02117 $3.99

 

[ummduh]

I got my adapter at sears. They aren't easy to find. I went to home depot, the local hardware store and was about to just order one online.

I have changed my fluid a few times now and I can't tell that the modifier is making any difference to the whining. I have tried both adding almost a full tube of the stuff from advanced auto, to last time only doing the recommended amount. I don't think it makes a difference.

The friction modifier won't make any difference. It is only used to keep the clutches in the limited slip from being too grabby. It makes the fluid more "slippery". It doesn't have anything to do with viscosity or any such stuff.

 

[Techniker]

I hate to point out the painfully obvious, but replacing the fluid is probably only covering up the problem- mechanical wear and probably could have been prevented through regular RD changes. Yes, the fluid can wear out, but sounds are never good. Drain plugs can be made easier to remove by spraying with PB Blaster or another penetrating oil (I like liquid wrench for its price) and allowing to soak. For really stubborn plugs, soaking and then moving the breaker bar in both directions with another spray of penetrating oil seems to help a lot.

-Tech

 

[Techniker]

I dont get it:scratch:

The "special tool" is a common ratchet. Could be 3/8" or 3/4" or 1/2" depending on which drain plug and the year of the vehicle.

 

[XCAMP]

I hate to point out the painfully obvious, but replacing the fluid is probably only covering up the problem- mechanical wear and probably could have been prevented through regular RD changes.

-Tech

Yeah, to be clear, what's causing the noise is pretty well documented and understood, and there's also a TSB out for it, so it's not a maintenance issue. The solution is widely known as well, but I can't see paying a few grand to quiet a noise that many have said just came back again a short time later, and that doesn't appear to cause a complete failure. If it was under warranty, I would certainly get the TSB work done.

That said, it hasn't gotten any worse or caused any problems, so I just ignore it these days. It does fluctuate with the outside temperature, maybe due to the oil viscosity, which is why I thought I could shut it up a little with more or less friction modifier, but maybe mixing some mud in would be a better solution. Fun stuff!

 

[Techniker]

Yeah, to be clear, what's causing the noise is pretty well documented and understood, and there's also a TSB out for it, so it's not a maintenance issue. The solution is widely known as well, but I can't see paying a few grand to quiet a noise that many have said just came back again a short time later, and that doesn't appear to cause a complete failure. If it was under warranty, I would certainly get the TSB work done.

That said, it hasn't gotten any worse or caused any problems, so I just ignore it these days. It does fluctuate with the outside temperature, maybe due to the oil viscosity, which is why I thought I could shut it up a little with more or less friction modifier, but maybe mixing some mud in would be a better solution. Fun stuff!

Thanks for the response. Or you could do it the used car dealer way- sawdust in the gearbox. Keeps it quiet until the gears blow out. That's interesting about the TSB and I'd be interested in reading up about it. Do you remember which TSB # it is or have a link? I tried to look up a TSB on a Ford once but after page #76 of drivetrain TSBs gave up.

 

[XCAMP]

Yeah sawdust might work better... it's TSB 05-12-6

 

[gcbimmer]

Need help...I just pulled fill plug....

I just pulled the "fill" plug for the rear differential and about 8-10 ounces of fluid came pouring out. This is my first time doing this and did not expect to have any come out when pulling the "fill" plug. Is this normal? Bought this 2002 XLT used so not sure what to expect. I thought when filling it just filled up to the fill plug, not over. Is that correct?

Thanks.

 

[tower]

On level ground it should be up to the bottom of the fill plug, having said that I always trying to get some extra in there.

 

[gcbimmer]

On level ground it should be up to the bottom of the fill plug, having said that I always trying to get some extra in there.

I filled it up to the fill hole and sealed it up. Took it for a ride and it seems to be louder theen it was before I changed the fluid. I am going to pull the fill plug again today to see if maybe the fluid worked its way in and I can get some more in there. It looks like I have the non-slip differential. Do you think I should add friction modifier? Could that hurt a non-limited slip or open differential? Will it help?
Thanks.

 

[JoshMcMadMac]

I filled it up to the fill hole and sealed it up. Took it for a ride and it seems to be louder theen it was before I changed the fluid. I am going to pull the fill plug again today to see if maybe the fluid worked its way in and I can get some more in there. It looks like I have the non-slip differential. Do you think I should add friction modifier? Could that hurt a non-slip differential? Will it help?
Thanks.

You need to get the friction modifier in there.

 

[gcbimmer]

You need to get the friction modifier in there.

So I should add it even though I do not have the limited slip differential? The post I read say only to add it if you have limited slip which I do not.
Thanks.

 

[Exproblems]

So I should add it even though I do not have the limited slip differential? The post I read say only to add it if you have limited slip which I do not.
Thanks.

If you "do not" have a "limited slip diff" but rather have an "open diff", you "do not" have to add friction modifier. Friction Modifier is only required for "limited slip diffs", but if you happened to add some by accident to an "open diff", the friction modifier will not hurt the open diff in any way.

 

[jstorm001]

I'm thinking about doing mine also I'm sure it was never changed looks easy for the rear but how about the front is it just as easy?

 

[gcbimmer]

If you "do not" have a "limited slip diff" but rather have an "open diff", you "do not" have to add friction modifier. Friction Modifier is only required for "limited slip diffs", but if you happened to add some by accident to an "open diff", the friction modifier will not hurt the open diff in any way.

Would adding friction modifier quiet the humming to any degree on an open differential?

 

[Exproblems]

Would adding friction modifier quiet the humming to any degree on an open differential?

On that, I do not know if it will help with a diff humming noise. Some people in here have claimed using "Royal Purple" gear oil has quieted down the rear diff humm.