When I make a turn at low speed I get a noise and vibration from my rear end. From what I have read from my repair manual it is best to take it some ware for repair because uf the specialized tools needed. Has any one else had a similar problem and if so what cos am I looking forward to.

 

if it only happens at low speed only during a turn, it is probalby the Limit Slip clutch in the rear axle. Check the tag on the axle to see that you have a LS unit. The oil in the rear end is getting old. You need to remove the cover, clean out the crud, install new 75 w 140 oil and a tube of fritcion modifier to it. IT treats the oil and makes the cluth not grab so hard. The modifier cost about $10 for a 7 oz tube at Auto Zone.
If your oil is not original, you might just buy the tube and add it to the rear end oil.

 

Thanks Steve. I'll give it a try.

 

Im a driveline tech at a Ford dealer, and Im not gonna say that adding friction modifier to the fluid wont fix the problem but lets just say we have tried that before and I personally have never fixed clutch pack chatter without replacing the clutch packs themselves. I only say this because if you are planning on replacing all of the fluid and adding friction modifier that is a good chunk out of your pocket since Motorcraft 75w140 is like $20 a quart. Good luck with whatever route you take

 

Well that sucks!

If I have to have the clutch packs replaced could you give me an idea of the cost I would be looking at.

 

Depends on which differential you have. If you have a 4.2/4.6 it will have the 8.8 rear diff which any Joe shop could take care of but if you have the 5.4 you have a 9.75 rear diff which requires a special spreader tool to remove the clutch packs and the ring gear and carrier have to come out of the truck. I can do an 8.8 in the truck with no special tools and with pulling only one axle. So cost depends on what diff you have.

I would say if you had to go to the dealer you are probably looking at the better part of $600. A non dealer shop may be in the $450 range. Just guestimates, depends on the shop, local labor rates and what not.

 

Let me also mention that clutch pack chatter is nothing more than an annoyance. I have never seen a rear diff fail because of clutch pack chatter. If you can deal with it, save yourself the money and leave it be.

 

LLADNAR, I have lived with my rear end chatter for over 2 years while I have owned my truck, however it seems to have gotten a bit worse. My truck has 102,000 miles and probably the original fluid in the diff. I was planning on doing a fluid change back there and was hoping it would quiet the chatter down a bit if not eliminate it completely, however I have heard hit and miss stories about whether or not it will be eliminated completely. Do you recommend any particular brand of fluid and friction modifier to use to have the best chance? Would Ford's brand be the best? Also, glad to hear it doesn't cause any harm, I was beginning to wonder if it was, but I didn't think so.

 

I personally would go with Motorcraft fluids, they are crazy expensive but they are the best in my opinion. At the very least use the Motorcraft friction modifier if nothing else.

 

Have you seen the fluids quiet the chatter down at all?

 

Honestly if it does it will be minimal. The real deal is once they start chattering they are pretty much gonna do it until they totally wear out. They basically chatter because of 2 things friction material that is transfered unevenly from the clutch discs the the steel discs. And the steel discs becoming wavy from the chattering. It is hard to describe but i have seen them apart before and there are marks across the discs that look like they skip on one another.

 

How much life do you think they have left? Should I replace them now if I plan on keeping the truck awhile? How many hours would you think it would take a dealer to do the job if I had the parts? i get wholesale pricing on parts from my ford dealer, but it may be easier/faster just to have them to the replacement.

Also, if I do just change the fluid in the diff. Is there any method to cleaning out any sluge/junk? I only ask because I pulled my rear abs sensor and it had some junk built up on it, I am just wondering how the rest of the rear end looks.

 

you can drive on them like that as long as you can put up with it really. And the amount of time it takes depends on what axle is in it. the 9.75 will take a little longer. If i were to get that job in the morning i would have it done before lunch time. I would stick with ford parts on the clutch packs. And as far as cleaning out gunk in the diff. We use brake clean to wash out the housing.