Replaces the worn friction and steel plates plus side gear thrust washers in a Ford 8.8 Traction-Lok that has stopped locking up.
If your Mustang, F-150, Explorer or Ranger leaves one black stripe instead of two, spins the inside tire pulling out of a wet intersection, or chatters and binds through tight parking-lot turns, the Ford 8.8 Traction-Lok clutch packs are the usual suspect. This is the Motive Gear F88CPK clutch pack kit, OEM reference F8.8CPK. It goes inside the carrier you already have and replaces the friction and steel plates plus the side gear thrust washers that set clutch preload.
A Traction-Lok is an open differential with a clutch pack stacked behind each side gear. A preload spring between the side gears squeezes both stacks, so the side gears are always partly tied to the carrier. When one tire loses grip, the clutches resist the speed difference and push torque to the tire that still has traction. Under load, the gear separating force from the pinion gears clamps the packs harder still.
The eared plates lock to the carrier and the splined plates lock to the side gear. Every turn the vehicle makes, those plates slip against each other, which is why they wear and why the axle needs a friction modifier in the gear oil. As the plates wear thin, the stack gets shorter, spring preload drops, and the unit slowly turns into an open differential.
Chatter alone is not always worn plates. It can also mean the gear oil was changed without friction modifier. Drain and refill with the correct modifier first; if the chatter returns or the axle still acts open, rebuild the packs.
Lift the rear, put the transmission in neutral and turn one wheel by hand. A healthy Traction-Lok makes the opposite wheel turn the same direction or resist noticeably. If the other wheel spins freely the opposite way, the clutches are not holding. For a firmer number, your workshop manual gives a breakaway torque check with one wheel on the ground. Also look at the cover: if the housing is full of chipped gear teeth or the pinion bearings are loud, plan a bearing job with the Ford 8.8 master bearing and seal kit while the axle is apart.
Motive Gear lists the F8.8CPK for the Ford 8.8 inch 10-bolt rear axle, with applications including the 1986-2006 Mustang, 1991-2002 Explorer, 1983-2002 Ranger, F-150 through 2004, 1997-2002 Expedition, 1986-1996 Bronco, 1987-1997 Thunderbird and 1988-1997 Cougar. The listing states it covers both 28 and 31 spline carriers. Not every one of those vehicles came with an 8.8 or with a Traction-Lok; Rangers and Mustangs were also built with the 7.5 inch axle. Count the cover bolts (the 8.8 has ten), read the axle tag, and confirm a clutch-type limited slip before ordering. Later Super 8.8 axles are a different design. If in doubt, send us the year and VIN. More axle and carrier service parts are on our rebuild kits page.
Want shims, a lock bolt and friction modifier in the same box? Compare the Ford Performance M-4700-B Traction-Lok kit.
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Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
The listing states it covers both 28 and 31 spline Ford 8.8 Traction-Lok carriers. Confirm your axle is an 8.8 with a clutch-type limited slip before ordering.
No friction modifier is listed with this kit. Ford's Motorcraft chart calls for XL-3 Additive Friction Modifier in Traction-Lok 8.8 axles, added before the gear oil.
Not for a clutch pack swap alone. The packs come out through the side gears once the axles and cross pin are removed. Ring and pinion setup only comes into play if you are also replacing bearings or gears.
The listed applications run through the mid-2000s. Later Super 8.8 axles use a different carrier design, so check the axle tag or send us the VIN before ordering.
Try a gear oil change with the correct friction modifier first, since chatter often comes from tired oil or missing modifier. If chatter returns, or one wheel still spins freely, the clutch plates are worn and this kit is the fix.
With the rear raised and the transmission in neutral, turn one wheel. If the other wheel turns the same direction, it is a limited slip. If it turns the opposite way, the unit is open or the clutches are worn out. The axle tag code also identifies it.
