Transmission Fluids

Liquid used in the automatic transmission, carries out diversified functions

  • Twisting moment transfer thru torque converter to the transmission
  • Maintenance of control systems and controls (computers) functioning
  • Work of frictional disks 
  • Greasing and cooling of the rubbing parts 

A special mineral oil received from oil and mixed with several special additives is used in automatic transmissions. This fluid is called as transmission's hydraulic lubricant. Use of other types of oils reduces the maintenance characteristics and can lead to transmission's breakage. The types of liquids used, as a rule, is specified on a dipstick of an automatic transmission (if applicable) or in the car passport.
In the majority of vehicles with automatic transmissions, these types of oils are used: “DEXRON-III”, “DEXRON-IV”, “DEXRON-V” and other synthetic oils. Mixing them is not recommended. 

Checking transmission oil

In the majority of cars the transmission oil level in an automatic transmission is checked with a running engine and the selection of gear in position ”P” (in some vehicles in position “N”). Most of the vehicles have dipsticks used for oil measurements (cars with sealed transmissions –do not). They have some labels. When the oil is heated up to a working temperature (180 – 210 F), the two top marks, correspond to normal level of transmission's oil. Often this site of the dipstick is marked by a notch and/or an inscription “Hot”. It is necessary to drive the car 5-10 miles for the oil in the transmission to get to this working temperature. After the oil warms up, it is important to establish the car on an equal, horizontal platform. Pull out the dipstick from the transmission, wipe it dry, insert it back until the end, and pull it out again. The lowermost, dry place on the dipstick will correspond to the transmission's oil level.
Attention! Many new vehicle models carry sealed transmissions and do not have the dipstick. These types of transmissions can be serviced only by professionals in the transmission shops. 

Replacement of transmission fluids

Replacement of transmission fluids should be made in specialized transmission shops. Such replacement can be made at our transmission shop. The procedure usually takes 30-40 minutes. In addition, if it is required to replace the filter, our technicians will replace it, and will make diagnostics of a real condition of your transmission. After all, much can be told about a transmission's condition from the smell and color of the fluids, e.g. dark brown or black color in a combination to a burnt smell speaks about transmission's malfunctions.


For transmission's proper work maintenance and its durability it is necessary to support an optimum level of oil and to update the used fluids It is recommended to change the transmission fluids every 15-20 thousand miles.. The operation term of transmission's fluids in many aspects depends on the age and mileage, and conditions of its operation.
Especially it concerns old, second-hand vehicles. This results from the fact, that these cars have been strongly used and worked in severe constrains. Besides, the part of fluids remains in the torque converter, the valve body, the pump and other cavities of transmission, therefore in a manual way it is possible to replace only half of the used volume, that means it is only more of the fluid update - than its replacement.

Danger of modulation/incomplete filling of transmission fluids

A very low level of transmission fluids is dangerous and it can cause the pump to grasp air together with oil. Because of that, oil is not compressed as it is necessary for the disks of friction clutches and it might cause a pro-slipping of disks against each other, and they can burn down. Operating the vehicle with the foamy oil in the transmission, will quickly put the transmission out of action.


If the level of fluids exceeds the admissible value, the transmission parts can foam the oil, too.
In both cases, the underestimated and overestimated levels of oil, foaming leads to increase of oil volume, and, because of that, to its emission through the transmission breather. That is the reason why it is very important to maintain the proper level of transmission fluids at all times.