Texotic

I thought TSB's were only covered under warranty... they're just instructions to help technicians fix common problems.

It has right at 34K miles. But, I do autox it and have done a track day at Texas World Speedway... and I have 285 tires, so I'm sure the bigger contact patch makes the clutch discs slip a lot more than the stock tires would have. I also bought it used with 19K on it, so I don't know how the previous owner treated it.

How much does that friction modifier cost, where do I get it, and how do I put it in? Sounds like it's worth a shot.

jmk3

Try the friction modifier, I used 2 oz. (1/2 bottle) & it cured mine. I used ford friction modfier.
Get it at the dealer or online.

AlloySixxer

Similar situation for me...I have a brand new 8.8 with 3.73s and at 35-40 mph I can hear a sort of whistling sound coming from the rear. It's only at these speeds and nowhere else. I'm sort of confused since this is a brand new rear end and the gears are installed to spec...

tx_zstang

Doesn't really sound like the clutch packs to me with the limited mileage and track usage you've seen. But it is strange that it's now doing it and it wasn't before!
What did they do again at the dealership?

The friction modifier can be gotten for under $5 for a 4 oz bottle, but that usually is needed for turning noises, not highway speed noise! (the clutch packs will slip when you turn or even apply a lot of power to the rear, other times they wont move, or shouldn't).
If you do need a clutch pack rebuild, there are instructions around (I've seen them), and it's a job yes, but can be done.
...but what did they do at the dealership, what did they f-up?

[...Gig'em ]

Texotic

Well I've had noises out of the clutch packs for about a year now, but the other day, this sounded kind of like that, but a lot more prominent. There's also been once or twice that I get a short groaning sound at low speeds when I hit the brakes, which shouldn't have anything to do with the clutch packs...

I have no idea what they did at the dealership... I left it there for them to figure out what was wrong with it and picked it up later in the day, payed them $49, and they told me "Yeah, you're right, it's the clutch packs."

I only notice the sound when I'm first speeding up and when I'm making tight, low speed turns. There isn't a peep out of the rear end at highway speeds... at least none I can hear over wind noise, tire noise, rattles, etc.

tx_zstang

Ok that helps; the noises at low-speed turns can usually be cured with 4 oz of friction modifier; try that first for at least a week (takes awhile to work its way in real good). If no help, then yeah, I'd say the packs need rebuilding.

If you never had friction modifier in there added then the life of your clutch packs may have been shortened. They made it a TSB to add it for our '05's after the fact, so you probably don't have any in yours.

Are your gears stock/has the rear end cover ever been removed and fluid replaced?

Let us know what you do and find out.

Texotic

The rear end has never been opened to my knowledge... I was in an accident last year where an axle got bent that needed replacing, so they might have opened it up then. They supposedly have a lifetime warranty on all the work they did, so if they did open it up, I might be able to get them to fix it for free, which would be sweet... I'll give em a call tomorrow.

tx_zstang

OK, that's good to know. They had to remove the differential cover to replace the axle. As a result, when fluid was put back in, no friction modifier was likely added. It didnt show up as noisy right away, but proabably over time it did and is now noisy at times.

Sounds like friction modifier is a good bet at this point, IMO.