[78 GHOST]

I have a problem.

My F-150 has had a long history (5 years) of rearend chatter accellerating at low speeds around tight corners (especially to the right.)

I know with the LS diff. you're probably going to get a small amount of chatter, which I understand.

However, today it made a really expensive sound in the same circumstances is usually would chatter.

Basically, I think the clutches (or whatever Ford used) are wasted and I need to either rebuild or replace the diff.

I've set up exactly 1 differential (the 12-bolt in my GTO) and it seems to be hanging in there.

Does anyone know if the Ford is harder to rebuild than a 12-bolt, or what?

Thanks in advance, Matt

[mechanickeith]

PM sent!

[stimpy]

thats the guy to have answer your question ^^^^^^

[mechanickeith]

I know nothing!!!!!!!!!!!!!!!!

[mechanickeith]

Regular F150 or Heritage edition??

Also, see if you can find a axle ratio tag on the diff housing assy. That info may be helpfull aslo.

[Bill Eveland]

If it's an 8.8 alot less special tools are needed. If it's a 9.75 you'll need quite a bit more to get it done. We used to do these on a regular basis at the dealer. I'm sure Keith has done a few himself and filled you in on the details.

The 8.8 will need the carrier and also ring gear removed to remove the s clip between the side gears , than the side gears are rolled out and the rest will come out. Just make sure to stack everything back together like the old clutches. With using the clutch pack gauge pack I end up using the smallest shim that comes with the clutch pack which is .030" on every one I've done.

The 9.75 is another whole differant deal, no s clip between side gears, but the bellville spring behind the clutch packs will need compressed with special tools just to roll the side gears out. Also will end up using the .080" shim along w/ the Ford kit.

If you end up doing this make sure to soak the clutches in friction modifier for 15 minutes before assembly. Be sure to get the Ford clutches, they have been updated for this issue.

[78 GHOST]

Keith, it's a new body style '04, not the heritage. It is a SCrew, and I believe the tag said 3L55 (3.55:1 and Limited Slip if I'm reading the shop manwell correctly)

I popped the diff. cover today to take a peeky pooh and to drain and refil with some Royal Purple. The gear oil was definitely wasted, dark brown and the diff cover was pretty cruddy with a thin layer of sediment.

The pattern on the gears looked good, better than I could probably get them. The teeth were pristine.

Bill, on the side of the carrier was a 9.75 cast into the housing.

Surprisingly, the hard part was adding the lube. I took a very short test drive and attempted to get things to mis-behave and didn't have any unusual noises or chattering. I'm going to put a few miles on it tomorrow and we'll see...

On a side note, I was reading about the front end and tested the ball joints for that knock.. no luck.

However, I'd like to know where you get a SuperMan torque wrench as the shop manual is stating some huge numbers for several of the front end fasteners.

ie: The lower Shock/Strut nut is to be tightened to 331 ft lb!!! OoooKay. And exactly WHO can generate this kind of force.. BTW, the engineers evidently thought 330 ft lbs wouldn't do it and 332 was overkill!


Seriously guys, thanks for the heads up. Bill, is that compressor available? What should I pay for that tool?

[INJUNTOM]

One thing that I found when I was at the dealership is that you need twice the amount of that Ford posi lube than you would think. It takes 2 bottles in the smaller stuff like explorers, etc, and 4 bottles in the F350s, etc.

We had a lot of vehicles with chatter maneuvering parking lots, etc.

[Bill Eveland]

I'll check and see if it has some otc #'s on the tool set up, it might not be worth it for a one time deal. Unless you know someone at the Ford dealer and they can loan it out maybe? To get the lube worked in , go drive some figure 8's. The tool fits in between the side gears and pushes them apart, it has to be compressed just right to get it apart, too loose or too tight and the carrier won't turn.

They make another tool that clamps in a vise thats splined like the end of the axle shaft to hold one side gear while the other is turned out. That still takes a big bar that fits in the carrier to turn it. You may be able to use your axle shaft itself to do that. If you don't mind clamping it in a vise anyway.

[mechanickeith]

Per vin # it is a 8.8 diff. As Bill said, the ring gear & carrier assy will have to come out after the axles are removed. Not hard to do at all. Ditto on the 2 bottles of friction modifier. 2 axle gaskets, 1 pinion seal(if needed) & the center section clutch disk kit for the 8.8 is about $175.00 . There was a tech service bullitin issued on this diff for this complaint. TSB 06-4-4 Issue is 8.8 limited slip diff may exhibit a chatter, shudder, or binding sensation during low speed turns. The clutch pack part # is F5AZ-4947-BA for the 8.8 diff.