dont forget your friction modifier!

[E-rock]

just a note that when your doing differential fluids (on posi-trac rears), even though ford says it never needs to be changed (lube-for-life), it surely does. but dont forget to get your gear oil with a friction modifier additive. i didnt notice when i bought the synthetics that it wasnt added and had a vibrating problem for weeks. i went to the store the other day and bought the modifier and once again life is grand.

 

[Turdle]

Dead Link Removed

For limited slip differentials-
Also called slip lock

 

[jpoprock]

Sorry for the dumb question... but I have this rear axel chatter and my Ford service guy told me that I'd have to get the clutches replaced to fix it. Honestly, it's been doing this for a LONG time. Some doofas as the dealership told me, while under warranty, that it was "the way AWD vehicles sound". Well, I've since learned, now OUT of warranty, that this is NOT the case. So, I'm mad. I'm going to chew someone down there at the dealer to get them to cover this. Anyway, if I buy some of this stuff, it's not guarantee that it will work. But my question is, HOW and where do I pour this stuff? One can and pour it in? Do I have to drain anything? Replace anything?

Thanks!
Jason

 

[aldive]

Not needed with most synthetics.

 

[CDW6212R]

The clutches are extremely easy to replace, with the axles out. If changing diffs think about the Zexel Torsen units, they have no clutches, never wear out, don't need modifier. Regards,

 

[jpoprock]

The clutches are extremely easy to replace, with the axles out. If changing diffs think about the Zexel Torsen units, they have no clutches, never wear out, don't need modifier. Regards,

Let me clarify something here... you guy are saying that I don't need the modifier? I thought that I did? What are you going by to establish this?

I'm going to hammer Ford garage to replace my clutches. I'm assuming that even thought the car drives and pulls nice that 50K miles of slipping has maybe ruined them? Maybe not.

I priced the 85/140 Synthetic oil at Auto Zone at like $16 a bottle. I think I read that it usually takes like 4 of them? And I DO NOT need the modifier if I'm using synthetic oil correct?

Thanks!
Jason

 

[techieman33]

You don't need it with MOST synthetic oils. It should say on the bottle weather you need it or not. Were you still using the fluid that came in it from the factory when you started to have problems? If so it already had the friction modifier.

 

[BryanB]

....and don't forget to wear gloves and wrap it up in a plastic bag. STINKY STUFF!

 

[CDW6212R]

If nothing is functionally wrong then just change the fluid, and add a friction modifier(traction lock). It's a $5 bottle easily found. If you had to change the diff, then don't pay top dollar for a stock traction lock. There are several better choices in the aftermarket.

Factory 8.8 traction locks don't last long at all when used. The rebuild kits are just over $50. Good lcuk,

 

[jpoprock]

Thanks for the tips guys. I must say that I'm a total NEWBIE when it comes to stuff like this. I don't do vehicle repairs. I have a brother in law that can though. All i know, is I have that "shutter", and the limited slip. The Ford guy told me I probably needed new clutches and it would cost like $650.

In reading on here today, some claim that adding a bottle of the Friction Modifier did the trick. But if you open that housing up, doesn't the old oil drain out? Shouldn't one just drain/suck it all out and add all new? THAT I can handle. But when it comes to replacing the clutches myself, I'm not sure that is something I'm willing to try on my own. I just don't know. If it's EASY my bro in law could do it, but I dunno.

And since my Explorer has had this shutter for a long time, I'm curious if my clutches are damaged, etc. How can you tell? I'd much rather just change out the fluid if that fixes it. But I guess there is no way to tell until you try it huh?

Thanks!
Jason

 

[aldive]

I have over 130k miles on my '99 with a 3.73 LS rear. I have used Mobil 1 and am currently using Amsoil synthetic and have NEVER added a friction modifier. I have never had any noise or other issues.

 

[jpoprock]

So is there a CHANCE that if I change this fluid out, with the Mobil 1, that my shutter may very well disappear?

The one thing that bothered me about what the tech said at Ford, was that "having the shutter wasn't hurting anything and causing no damage". Can this be true?

So, I take the bolt out, drain it, and add roughly one bottle of that big 'ol container of say Mobile 1 and be done with it? That's it??? Seems like a 20 min job.

Thanks!
jason

 

[CDW6212R]

Those later trucks have both a drain and fill plug back there don't they? The fluid should be just over two quarts I think. There have been rear differential issues with the 2002+ models, every symptom has been described by Ford as normal. I've been wary about that kind of conclusion. Some people have lived with it, and others have managed to get new parts.

Change the fluid and see what you get. If the fluid doesn't help and you have to go back in soon, you can drain and reuse that fluid. Good luck,

 

[jpoprock]

I know for sure that I had something like Rear Axel Seals go bad. THey replaced them under warranty and they leaked again. They replaced them a 2nd time and they have never leaked again. They claimed there was a probl with the manufacturer of the seals. I don't think it's related to my shutter though. I'll check it out.

Is there a way I can find out for sure how much fluid the case will take?

Jason

 

[rizzjc]

Should be in your manual. It get a couple/three quarts and fill until it spills out the fill plug. I use to have my rear diff fluid changed, so who knows what they put in it, but I have had Amsoil in there for the past 60k miles or so. I don't have friction modifier.

 

[CDW6212R]

The magic fill number is like 2.25 quarts, buy three.

 

[Ford_Racing_Guy]

Not needed with most synthetics.

does Mobil 1 have the proper additives?

 

[gijoecam]

Mobil-1 does not have the additive AFAIK.

You only need the additive if you have a Ford Trac-Loc Limited Slip Differential. If you have an open differential, there is not need for the limited slip additive.

Now, once it starts chattering, in about half the cases I've seen on here, adding the additive is all it takes to fix it. In the other half, adding the additive doesn't fix it, and still necessitates replacement of the clutch pack. It's a $5 bottle, so it can't hurt to try it first.

Also, $650 is WAY high for a rear end rebuild. You could install any number of higher-quality limited slips for that price. (Torsen included, although I like the Detroit TruTrac personally). Find a good driveline shop in your area and use them. Don't let the dealer rake you over the coals like that.

-Joe

 

[jah81592]

....and don't forget to wear gloves and wrap it up in a plastic bag. STINKY STUFF!

Smells like money to me!

 

[410Fortune]

I have run into some people (Axle builders / off road shops,. etc) that use friction modifier no matter what. Open, LIMITED SLIP, lockers, etc they ALWAYS add the stuff to gear lube.

It reduces foaming in all situations

Just passing this one...I run the modifier in my ARB locked otherwise open 8.8
What can it hurt?