USA Standard Spartan Locker 8.8in Ford Spartan Locker Cross Pin

A grooved, bent or cracked cross pin is one of the most common things people find when they open a Ford 8.8 that has been clunking, and it is just as common in a Spartan Locker that has seen hard use. USA Standard Gear part SL XP-F8.8 is a heavy-duty replacement cross pin shaft for the Ford 8.8 inch rear with 31-spline axles. It measures 7/8 inch outside diameter and works with the Spartan Locker or with standard open spider gears, so F-150, Explorer, Expedition, Ranger and Mustang owners can replace a worn pin without buying a whole locker.

What the cross pin does in a Ford 8.8

In the open 8.8, the cross pin passes through the carrier case and carries the two pinion gears. A lock bolt holds it in place. The 8.8 uses C-clip axles, and the cross pin is also the stop that keeps the axle shafts from sliding inward, which keeps the C-clips seated. In a Spartan Locker the same pin runs through the drivers and takes every bit of torque that goes through the locker. When it wears, you get slop, noise and eventually a broken pin or bolt.

Symptoms of a worn or damaged cross pin

• A clunk from the rear when you go on and off the throttle or shift from drive to reverse
• Visible grooves, flat spots or galling on the pin where the gears or drivers ride
• A sheared or loose lock bolt, with the pin starting to walk toward the ring gear
• An axle shaft that moves in and out because the C-clip has lost its stop
• Extra clicking or banging from a Spartan Locker beyond its normal ratcheting in turns

Whine, howl and bearing noise are different problems; our Ford 8.8 rear axle problems guide walks through which noise points to which part.

How to confirm before you buy

Pull the cover, remove the lock bolt and slide the old pin out. Measure it with calipers: this shaft is 7/8 inch (0.875 in). Check the spline count on an axle end too. This pin is listed for the 31-spline 8.8, and our Ford 8.8 28 vs 31 spline guide shows how to tell them apart. If your pin is a smaller diameter, do not force this one in.

Fitment

SL XP-F8.8 fits the Ford 8.8 inch rear with 31-spline axles and a 7/8 inch cross pin. USA Standard lists it as a replacement for the shaft that comes with the Spartan Locker SL F8.8-31, and it also works with the factory open spider gears in that carrier. It is not for Traction-Lok limited-slip carriers or the 2015-up Super 8.8, which uses a different carrier and 34-spline shafts. Spline count and pin size changed across years on the same truck names, so measure yours, or send us the year and VIN. More 8.8 parts are in hard parts.

Install notes

• Drain the axle, pull the cover, remove the lock bolt and push the pin out. With the pin out, push the axles in to free the C-clips if you are servicing the gears or locker.
• Inspect the pinion gears or Spartan drivers where the pin rides. If they are worn, a USA Standard Ford 8.8 master overhaul kit covers bearings and seals at the same time.
• The Spartan install manual notes that deep ratios such as 4.88 or 5.13 can block the cross pin; in that case the carrier has to come out to fit the pin.
• Install the new pin, line up the bolt hole, and fit the lock bolt with thread locker, torqued to the spec for your axle.
• Seal the cover with RTV or a gasket, or upgrade to a Yukon Hardcore 8.8 cover, and refill with the gear oil grade on your axle tag.

Not sure whether a lunchbox unit or a full carrier is the better path for your truck? Our lunchbox vs full carrier locker comparison covers the tradeoffs.

Does this cross pin come with a new lock bolt?

The listing is for the cross pin shaft. Reuse your lock bolt only if the threads and head are perfect; a stretched or damaged bolt should be replaced.

Can I use this pin with my factory open spider gears?

Yes. USA Standard notes it works with the Spartan Locker or standard open spider gears in a Ford 8.8 with a 7/8 inch cross pin.

Will it fit a 28-spline Ford 8.8?

It is listed for the 31-spline 8.8 with a 7/8 inch pin. Measure your old pin and check your spline count before ordering.

Does it fit a Traction-Lok or a 2015-up Super 8.8?

No. It is for open carriers and Spartan Locker installs in the standard 31-spline 8.8, not limited-slip carriers or the Super 8.8.

Do I have to pull the carrier to replace the pin?

Usually not. With very deep gear ratios like 4.88 or 5.13 the ring gear can block the pin, and then the carrier has to come out.