limited slip ??
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limited slip ??
I have a h9 rear diff in my 94 (3.55 limited slip) I was backing up a muddy wet drive way today stuggling all the way up, I checked when I got out to see if both tires had been spinning, but nope just one, does this mean my limited slip is not working, or does it need different conditions than this to ingage, the diff had all new bearings put in just before I bought it, I talk to the guy who did the work and he claims he put that limited slip additive in, can someone shed some light on this for me Thanks Randy 
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From: Topsfield, MA
The factory unit has a clutch pack inside, there are six clutch disks, three on either side. Over time, these disks wear out and become thinner. The thinner they get, the less pressure is applied to them. When they get old, there's barely enough friction in the disks to provide the limited slip action, so basically you need a new clutch pack. Ford has them available for about $65, it's a traction lok (yes, lok) rebuild kit for an 8.8 (ask for that at the dealer), it'll have everything you need to rebuild it, very simple.
Mine had instructions in the box, but a haynes manual also has the information if I'm not mistaken.
Good luck with the repair!
Mine had instructions in the box, but a haynes manual also has the information if I'm not mistaken.
Good luck with the repair!
Postmaster
Joined: Dec 2002
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From: USA
In the meantime, sometimes you can get a limited slip to hook up by applying the brake a little while you're giving it gas. The braking adds resistance to the slipping wheel, making the torque difference between the slipping and non-slipping wheels less of a difference so the clutches can grab.
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Originally Posted by MustangGT221
The factory unit has a clutch pack inside, there are six clutch disks, three on either side. Over time, these disks wear out and become thinner. The thinner they get, the less pressure is applied to them. When they get old, there's barely enough friction in the disks to provide the limited slip action, so basically you need a new clutch pack. Ford has them available for about $65, it's a traction lok (yes, lok) rebuild kit for an 8.8 (ask for that at the dealer), it'll have everything you need to rebuild it, very simple.
Mine had instructions in the box, but a haynes manual also has the information if I'm not mistaken.
Good luck with the repair!
Mine had instructions in the box, but a haynes manual also has the information if I'm not mistaken.
Good luck with the repair!
Post Fiend
Joined: Nov 2001
Posts: 14,947
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From: Topsfield, MA
I think you could do it Randy, mainly you just need a micrometer or caliper, you need to put the clutch pack together, and snug it down with a small c-clamp. Next to the c-clamp, measure the pack thickness (with the shim installed), I believe the instruction sheet will tell you the correct thickness (add/remove shims to arrive at that thickness).
You could also measure the size shim that was originally installed, find the new shim of the same size, and just re-install it (the above method is more accurate though). You don't have to take the rear carrier out, just take the wheels/tires and drums off. Then pop the rear end cover, remove the small bolt for the pinion shaft, remove the pinion shaft, than push the axle shafts in as far as they go, use a pair of plyers to pull the c-clips, than pull the axle shafts out of the carrier (you don't have to pull them all the way out). Once that is out, you can remove the side/spyder gears (make sure you know which side they came out of) and gain access to the clutch pack. Install is the reverse of the removal.
Appling the E-brake w/ slight pressure works better than using the actual brake on that.
You could also measure the size shim that was originally installed, find the new shim of the same size, and just re-install it (the above method is more accurate though). You don't have to take the rear carrier out, just take the wheels/tires and drums off. Then pop the rear end cover, remove the small bolt for the pinion shaft, remove the pinion shaft, than push the axle shafts in as far as they go, use a pair of plyers to pull the c-clips, than pull the axle shafts out of the carrier (you don't have to pull them all the way out). Once that is out, you can remove the side/spyder gears (make sure you know which side they came out of) and gain access to the clutch pack. Install is the reverse of the removal.
Appling the E-brake w/ slight pressure works better than using the actual brake on that.
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would those clutch packs be worn out at a 100,000 miles? and I was wondering if the guy that did the bearings forgot to put in the friction modifier, would that cause the limited slip not to work?
Post Fiend
Joined: Nov 2001
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From: Topsfield, MA
The clutches could definitely be done by 100k, and a lack of friction modifier will make the LS work harder than easier....so no it's not from a lack of friction modifier.
The friction modifier is used to ease some of the friction in the clutch pack or it'll chirp around corners and such.
The friction modifier is used to ease some of the friction in the clutch pack or it'll chirp around corners and such.
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Joined: Jul 2003
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From: Ontario, Canada
Hold on a sec guys. I was going to ask a question regarding the limited slip diff. oil change but after reading this I got another questions:
How often do you supposed to change gear oil in limited slip diff? Since it has clutches that wear out, the worn out material floats around in the housing. Doesn't that material act as an abresive?
And my original question was: Should I change gear oil once the rear diff is broken in in a new truck?? Right now I have 10000 km (6000 miles) and I can see some residue suspended in the oil.
Thanks,
T.
How often do you supposed to change gear oil in limited slip diff? Since it has clutches that wear out, the worn out material floats around in the housing. Doesn't that material act as an abresive?
And my original question was: Should I change gear oil once the rear diff is broken in in a new truck?? Right now I have 10000 km (6000 miles) and I can see some residue suspended in the oil.
Thanks,
T.
Post Fiend
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From: Topsfield, MA
I'd change the gear oil and then add the appropriate amount of friction modifier. I change my diff oil every 30kish, depends. If I went through some water holes, it's a good idea to change it as some water may have gotten in there. The material from the clutch pack is minimal, and not something to be concerned about. Metal shavings are the worst, they ruin the bearings quickly.
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I HAVE A 2000 F-150 with what a vin says diff H9 , i replaced the oil and i looked very much in detail for any clutches,springs or anything that could indicate limited slip I DID NOT SEE NOR NOTICE ANY DIFFERNEC FROM AN OLD
PLANE REAR END one wheel drive, HOWEVER ;
WHEN I GO ARROUND CORNERS IT DOES SHUTTER , DOES ANY ONE KNOW WHY?
PLANE REAR END one wheel drive, HOWEVER ;
WHEN I GO ARROUND CORNERS IT DOES SHUTTER , DOES ANY ONE KNOW WHY?