Transmission Cooling, Basic Function - GF27.55-P-1000B

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Model All with transmission 725

Transmission oil cooling circuit

Courtesy of MERCEDES-BENZ USA

Overview

This document contains information on:

General
Function requirements
Function

General

Transmission oil cooling keeps the transmission oil temperature constant. This prevents overheating damage to the automatic transmission.

Function requirements

Primary pump
- Engine in operation
Electric auxiliary oil pump
- Ignition ON (circuit 15)

Function

The transmission oil is drawn out of the oil pan by a mechanical primary pump in the automatic transmission and pumped to the oil thermostat (3) through the feed. The oil thermostat (3) routes the transmission oil back to the automatic transmission through the return line at a transmission oil temperature < 90°C. At a transmission oil temperature of > 90°C, the oil thermostat (3) opens and the transmission oil flows through the additional oil cooler (2) and the oil cooler (1) before it flows back through the return line to the automatic transmission. In order to ensure needs-based cooling, the electric auxiliary oil pump is actuated in addition to the primary pump, depending on the situation.