Vapour Trails

Well after having my fuel pump replaced last week under a TSB, it looks like I have another common problem, rear differential noise on a tight, low speed turn. Just noticed it today in the grocery store parking lot. I switched drivers with my girlfriend and stood outside and she did tight turns and she and I agree the sound is coming from the rear of the car. 5 minute search on this great website alerted to me that this is fairly common.

https://mustangforums.com/m_1827456/tm.htmThis is a link to a long thread about the problem. The TSB is 06-12-11.

I just wanted some opinions here. The previous owner installed 4.10 gears, performed by a transmission shop. If I bring the car to ford for replacement of the clutch packs, does this include changing the gear set? TSB on the subject, 06-12-11,does not mention it.I have little knowledge of the inner workings of a differential.I certainly want to retain the 4.10 gears, but I also don't want to mention tothe dealerthat I have them, for fear they will blame the noise on the gears and refuse to fix it. Now this is probably being paranoid because they seem reasonable, but I generally try to avoid them knowing anything about the modified state of my vehicle if I can help it.

I've also heard the replacement clutch packs are thinner, what effect would this have? The above thread also mentioned something about LSD capabililtes being lost after fixing this noise.

Finally, changing gear oil or adding friction modifiers to the rear differential have seemed to help in several cases. Should this be my first course of action? Looking for any opinion on my situation.

Thanks again

hammeron

mine moans but it really doesn't
bother me...

good luck with yours tho, i hope
you get it fixed to your satisfaction

VerginaStang

well i had a friend replace mine under warranty, and i have 3.73's. its two seperate things, so they should warranty the work- but i avoided the hassle. Are you sureits not the gears making noise?

With my issue, I could FEEL a binding in the rear. Almost like a power steering issue when i made slow turns, except the feeling was the rear end, not the steering wheel (best i can describe it).

If it is the clutch packs, your gears do not have to be replaced.

moosestang

Mine groans in pain ever time I pull into my parking spot. It doesn't really start until I disengage the clutch, but i've heard it during tight turns with the clutch out as well. I'm just waiting for it to burn up so I can have an excuse to get a trutrac.

The thing won't die!

You should have heard it after the gear install. The shop didn't put any friction modifier in there.

Stkjock

i had that... went to a truerac and 4.10s!!!! solved the problem!

it will really depend on the dealer that u take it to. a good one will do the work w/o issue IMO

Vapour Trails

Did you mean to say shouldn't?

So damage will eventually occur if the problem is not fixed? Does friction modifier prevent damage or simply keep you from hearing the noise?

GRABBER GT

Change out the fluid and additive first and see if it improves.

The new clutch pack is installed with a greater clearance to alleviate the binding. The gears are not replaced.

ford4v429

My mark VII was making racket, changing the diff oil made it worse, then dumping in the friction modifier(oops- didnt know I was supposed to add that to the oil initially) and all quiet...that little bottle of stuff really makes a huge difference in the way the clutches slip- without it , it tried to bark the insidetire intermittently on a tight turn, with it, smooth as silk.

moosestang

No I meant should. It made a god awful amount of noise because the shop didn't put in any friction modifier. The friction modifier let's the clutch packs slip when turning.

Vapour Trails

OK, this friction modifier, can I just add it without draining the current fluid? How much is in one bottle? Thanks