Internal Gearing Transmission Oil Pump DHT

Automatic Transmission Oil Pump classification
According to whether the displacement of the oil pump can be changed, automotive automatic transmission oil pumps can be divided into quantitative pumps and variable displacement pumps. Common definitions
The metering pump has two types: external engagement and internal engagement. On construction machinery and trucks, due to the high power of the oil pump, it is difficult to arrange it inside the gearbox. Generally, external gear pumps are used and arranged outside the gearbox; The Lubrication Oil Pump is arranged in the box, and generally uses a compact structure and small size internal meshing Gear Pump. There are two types of internal gear pumps with and without a crescent shaped separator. When the difference in the number of teeth is greater than 2, a crescent shaped separator is required to seal. There are involute gear pumps with crescent shaped partitions, cycloidal gear pumps, cycloidal rotor pumps without crescent shaped partitions, and double center pumps. There are few examples of variable displacement pumps used in automotive automatic transmissions, and only GM is known to use variable displacement vane pumps.

Critical parameters:

Reasons of the oil pump malfunctions:

Generally, the oil pump failure may be caused by the following reasons:

- Installation of the transmission is performed incorrectly (wrong size of the end clearance);

- The ATF level is too low;

- Intolerable operation conditions (clogged mesh oil filter, high suction of intake pressure). It is also notable that the oil pump failure may be caused by misuse of the car during the winter season. Quite often, car owners do not warm up the transmission fluid, but start moving without any warm-up. As a result the oil does not have the proper viscosity status that leads to an excessive load on the oil pump. The oil pump rapidly fails to function under the influence of such loads.

- Rapid wear of the pump due to the aggressive driving style with abrupt accelerations and braking;

- Poor oil quality (rapidly becomes contaminated or does not correspond to current specifications); during operation, particles of settle down on mobile parts of the pump. This debris clogs pore spaces of the pump and puts it out of order. Frequently, transmission specialists have to deal with oil leakages caused by issues with seals or bushings;

- Disregard of the main car performance parameters (in particular, oil pressure).