In the foreground is a new...
In the foreground is a new center dog for a racing locker. As you can see, the teeth are still well defined. To the left of it is a worn dog. The gear teeth are rounded, and this unit should be replaced.
You may be surprised to learn that Ingram says the greatest area of wear on a typical rearend isn't the ring-and-pinion gears, but the locker. Lockers take a little abuse every time they activate, and the more horsepower you add to the mix, the tougher that abuse gets. One of the most sensitive components always seems to be the locker springs, no matter what brand is used. A good way to extend the effectiveness of your locker is to run an oil cooler, especially if you regularly participate in races that are 100 laps or longer.
After disassembling the locker, inspect the teeth on all the dog gears. They should have sharp, defined edges. Even if the drive isn't abusive, over time they will wear and will need to be replaced. If any of those edges are worn, replace them. Begin by placing the steel rings inside the locker housing that keeps the dogs from eating into the aluminum housing.
When reassembling the dogs, Ingram cautions that you should always use enough oil or gear lube to create a film between all the mating surfaces. When reassembled, the teeth of the dogs fit very tightly together and are held that way by the springs. So, even if the locker is surrounded by gear lube, it is possible for the dogs to remain dry until you get out on the track. It's also a good idea to replace the springs at least once per season. As mentioned before, it always seems to be the locker springs that are most susceptible to heat, and simply replacing them regularly is cheap insurance.
 Before assembling all the...  Before assembling all the differential components, make sure there is a film of lubricant between all the mating surfaces. |  Whenever you rebuild your...  Whenever you rebuild your locker, it is a good idea to replace the locker springs because they can be easily affected by heat. |  Tiger gear specialist Wayne...  Tiger gear specialist Wayne Ingram says both a spool and locker should be consistent on all critical surfaces within 0.002 inch. If runout in any area is greater than that, it can affect the consistency of the lash between the ring-and-pinion gears. |
The locker assembly goes back together into the housing, sandwiched with a spring on either side. The locker springs are quite strong, and it can be a frustrating task if you don't have a locker spring compressor, which is the proper tool for the job. Most gear specialists use a piece of threaded rod with flanges welded to nuts so that the rod can be inserted through the locker and the nuts can be threaded down to compress the locker enough for it to be bolted together. You can fabricate your own, but Tiger sells a locker spring compressor in its toolkit that works quite well.
When reassembling the rear...
When reassembling the rear end-even before test-fitting for crush and lash-the first step is to install the wear pad in the left-side bell. It is too easy to forget the wear pad later, which will have you tearing everything back down just when you thought you were done.
Before final assembly of the ring gear to the locker (or spool, if that is what you are using), you should make sure there are no burrs or dings in the material of either the ring gear or the locker that can affect the alignment. Sometimes the smallest grit caught between the back of the ring gear and the locker can throw off the ring-gear alignment enough to cause lash problems. Clean both surfaces with Emery cloth or a flat honing stone. Finally, don't forget to use red Loctite on all the ring-gear bolts, torque to spec, and safety-wire each of the bolts.
On a rebuild, you can usually use the same shims that came out of the assembly and get the correct amount of lash, but it is still a good idea to recheck everything just in case. Ingram says the correct amount of gear lash is between 0.008 and 0.013 inch, but he aims for the tight side because lash will always open up after the gears have been run in. On a rebuild, normal use will open up the lash to around 0.020, which isn't a concern.
Ingram always sets lash with the left side of the bell and axle tube attached to the centersection and pointed down. This means he builds from the right side of the housing. The ring gear and locker are set into place, and the centersection is dropped into place on top of that. Be sure to install the wear pad now so you won't forget and have to tear the rearend down again later.