How Differentials Work

An automotive differential is a set of gears placed in the driveline which splits engine power to the axles allowing the right and left tires to turn at different speeds. This is necessary because as a vehicle makes a right turn, the right tire will travel a slightly shorter distance. On a traditional rear-wheel-drive vehicle, a large ring gear is driven by the driveshaft. The ring gear is attached to a carrier. The carrier contains two sun gears (one sun gear is connected to each axle) and a pair of planetary gears that are meshed with each of the sun gears. During a right turn, the right axle turns slower causing the planetary gears to begin spinning inside the carrier. Slip-DiffernetialThe spinning of the planetary gears allows the left sun gear to turn faster than the right; therefore, the left wheel turns faster than the right one. In a straight line, the planetary gear only rotates with the carrier and ring gear and does not spin (except a tiny amount to make up for slight variations in tire size or road irregularities.) Front-wheel-drive vehicles have a mechanism similar to this contained within the transmission in front. Located in the Denver area, Rocky Mountain Driveline is your full service shop when it comes to auto driveshafts. We rebuild all types of driveshafts and CV axles. Give us a call so we can help you keep your auto in top shape at a reasonable price.

The open differential described above suffers from a lack of traction in some circumstances. This is because it supplies equal torque to each axle. If one tire is on ice and the other is on dry pavement, very little torque is supplied to the dry tire since only enough torque is distributed to spin the ice tire. Because of this problem, the “locking differential” was developed to supply maximum engine torque to both axles in almost all conditions. The “Detroit Locker” is a famous example. Some “lockers” can lock automatically or can be selectively locked by the driver. In either case, they provide the maximum available torque to the wheels making the axle act as if it were one piece. If you are in the Denver area and are having trouble with your driveline, give us a call and we will get you back on the road as soon as possible.

A part-time four-wheel-drive vehicle incorporates a front and rear differential with a transfer case. The transfer case when engaged causes all four wheels to be locked to nearly the same rate. A separate driveshaft from the transfer case is connected to the front and rear differentials. This causes some problems with drivability because poor traction on the opposing axle can result when any tire loses traction. The solution is to provide a “limited-slip” or a “locker” so that maximum engine torque can be applied.


Rocky Mountain Driveline can rebuild transfer cases and transmissions for your auto. We also provide brake work for antique and classic autos. We even fabricate custom carbon fiber driveshafts. If you are in the Denver area, give us a call and let us describe our services in more detail.

In an all-wheel-drive auto, there is a front, rear and center differential to allow the wheels to turn at different rates. This makes the vehicle easier to drive than the conventional part-time four-wheel-drive. No matter what type of vehicle you drive, Rocky Mountain Driveline, located in the Denver area, can provide you with the highest quality CV axles and driveshafts at an affordable price.

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