Dual-Clutch Transmission Oil Supply, Basic Function - GF27.57-P-1002A

Transmission 700.420/421/422/423, 724.033/044/045/103/114/115/120 

Overview 

This document contains information on:

• General 
• Function requirements 
• Function 
  • Dual-clutch transmission oil supply 
  • Centrifugal oil lubrication 
  • Dry-sump lubrication 

General 

The oil supply system is responsible for the lubrication of all the relevant components in the dual-clutch transmission.

Function requirements 

• Engine management ON (circuit 87M)
• Engine in operation

Function 

Dual-clutch transmission oil supply 

The oil supply, lubrication and cooling of the dual clutch transmission is performed by the following procedures or components:

• Two oil pumps operating independently of each other, meaning the oil pump (primary pump) and an electric auxiliary oil pump or a dual clutch oil cooling pump
• Centrifugal oil lubrication running through gears in oil bath

The following dual-clutch transmission components require a constant supply of oil when in operation:

• Fully integrated transmission control electrohydraulic controller unit
• Gear sets and shafts as well as all moving component parts on dual-clutch transmission
• Dual clutch
• Gearshift actuator

The following types of oil supply are available:

• Centrifugal oil lubrication
• Dry-sump lubrication
• Through the oil pump (primary pump)
• Through the electric auxiliary oil pump
• Through dual clutch oil cooling system pump

Centrifugal oil lubrication 

The transmission oil is spun-on using the rotating gear sets of the dual-clutch transmission in the oil sump or forwarded to the engaged fixed or idler gears. The spun-on transmission oil is responsible for most of the gear set and bearing lubrication.

Dry-sump lubrication 

The transmission oil is delivered into the air intake chamber from the gear set chamber through the electric auxiliary oil pump and dry sump pump.

The dual clutch, as well as the gear set gearing, shafts and bearings, are cooled and lubricated by transmission oil from the fully integrated transmission control electrohydraulic controller unit.

On the one hand, transmission oil is fed directly into the air intake chamber and, on the other hand, it flows together in the gear set chamber (dry sump).

A lubricating spider lubricates the gear sets depending on the load request.