OK, Lets discuss differentials. First of all there are 2 basic types of rear end assemblies. The removable carrier where the entire assembly can be removed in one piece and the integral carrier where pieces are removed and replaced one at a time. If you have a series of bolts around the front of the axle and nothing on the rear housing then you will have a Removable carrier type. However if there are a series of bolts around the rear of the axle assembly and the yoke assembly is held on with a large nut in the center of the yoke, you most likely have an integral carrier unit.
Most high performance and V8 Mustangs were equipped with the removable carrier type units. These are the easiest to work on and the most desirable. Low performance mustangs (6 cylinders and some early 2bbl V8’s) received the integral units.
Now, next there are two additional categories that are sub-sets of the above sets. One can have a conventional rear end assembly or a “locking” rear end assembly. If you have a “locking” type rear end unit, it can be one of three different types; Limited slip, Traction Loc and Detroit locker. These will be discussed in more detail soon.
CONVENTIONAL rear ends are the oldest and most common rear end assembly used. They are still widely used today. In this type of rear end, the first tire to grip the road transfers the power to the opposite tire. Thus, only one tire is providing traction. And, if the first tire starts to spin and looses traction because of too much power or the road surface is slippery no traction is passed to the opposite tire and a total loss of traction occurs.
LOCKING rear ends have a series of clutch plates that transfer power equally to each of the rear tires. When going around a corner, a small amount of slippage is required and the discs allow this to happen. This slippage is necessary because the outer tire in a turn must travel a greater distance than the inner tire. I will now briefly discuss the three more common FORD locking rear ends.
LIMITED SLIP uses 4 steel clutch plates that are locked into the differential cover. 3 bronze clutch plates are splined to a clutch hub then to the left hand axle shaft. A spring plate provides constant pressure on the plates and equal power to each wheel. Because of the constant pressure between the clutch plates, the limited slip differential is fairly noisy, much more so than the conventional rear end.
TRACTION LOC differentials are very similar to the limited slip type except that it uses a preloaded spring plate and a block between the pinion gears and side gears. Its pre loaded springs release only when a predetermined load is encountered. Therefore the clutch plates remain engaged at all other times and the noise level of the differential is very low compared to the Limited slip axle. This is the best axle for street usage if you desire a locking rear end.
DETROIT LOCKERS are designed for racing purposes! They are solid and one cannot hardly damage one at the track with a modified racing engine. However they are noisy, and loud. But they are strong and durable and the best choice for all out racing.