5 minute read
The Direct Shift Gearbox - How they work, how they fail & how ACTRONICS can help
Whilst the production DSG gearbox is a comparatively modern revelation, the formation of the original conceptual development can be traced back to the 1970s, nearly threedecades before they would be supplied on mass into road going vehicles.
Spurred on by the fuel-crisis of the period, the German government endorsed a series of research programs to develop new ways to improve fuel economy. One project worked on by Porsche engineers, determined that there was a possibility to greatly reduce the fuel consumption of vehicles equipped with traditional torque convertor automatic gearboxes. They built a series of prototypes to test the idea, some were built into un-assuming models like the lowly 924, but by 1984, a version of Porsche’s revolutionary design would be fitted to a 956 racer.
The project was not a success at the time. After being plagued with reliability issues the technology was locked away in a back office, we’d like to imagine in a dusty folder. Nearly two decades later, Volkswagen would successfully launch the first production DSG Gearbox.
Despite being fitted into a performance focussed MKIV Golf R32, Volkswagen claimed that the gearbox could be up to 20% more economical than a traditional automatic gearbox with a torque convertor. The first DSG6 units, sometimes referred to as DQ250, utilised a wet clutch system.
In 2008, VW continued to develop the DSG gearbox and launched a development of the original. Now with 7-forward gears, the DSG7 was available in a far wider range of vehicles; everything from the Polo to the Tiguan.
The DSG’s gearbox ability to reduce the compromises of traditional automatic gearboxes resulted in a substantial increase in sales of “Automatic” transmission models. At the turn of the century, Volkswagen reported that more than 90% of all Golf models produced were supplied with a manual gearbox. By 2018, over 40% of all Golf models were supplied with a DSG unit, the rates are higher for other models, over 90% of all Tiguan Allspace models had a DSG transmission.
Common problems
DSG 6 – DQ250 (02E)
Faults related to solenoid valves (N215/N216/N217/N218/N233/N371)
Faults related to sensors
Failure to change gear
Gear changes are erratic
Error Codes: P1740/18148/005952
DSG 7 – DQ200 (0AM)
A short circuit in TCU and or blown fuse
Total electronic failure
005636/P1604 – Internal Control Module: Output Driver IC Error
16946/P0562/001378 – System voltage too low
Internal leak: P17BF – Hydraulic pump system overload protection
P189C/006300 – Function restriction due to insufficient pressure build-up
How do they work?
Mechanically, the DSG 6 gearbox is effectively a manual gearbox with two wet multi-plate clutches, two drive shafts, an input/primary shaft and two output shafts which are secondary. An electronically controlled hydraulic control unit, referred to as Mechatronic, ensures that the gearbox can operate fully automatically. Optionally, the driver can select a manual mode and control the gearchanges by themselves.
A dual mass flywheel connects the crankshaft of the engine with the two clutch housings (outer plate carriers) which together rotate in unison with the crankshaft. The two inner plate supports rotate independently of each other around the same shaft and each drives its own drive shaft via a fixed connection.
Drive shaft one rotates inside the hollow drive shaft two. On drive shaft one are the gears for 1st, 3rd, 5th and reverse gear; the gears for 2nd, 4th and 6th gear are on drive shaft two. When shifting from one gear to the next, the next gear is shifted from one drive shaft to the other, where the next gear has already been engaged on the corresponding output (main) shaft.
When shifting gears, the clutch to the drive shaft of the ‘old’ gear is decoupled in one smooth movement and the clutch to the drive shaft of the ‘new’ gear is coupled in one smooth movement. So, there is an overlap in the drive through both gears.
In normal operation, during upshifts, the engines torque is slightly reduced whilst the engine torque is slightly increased when downshifting. Overall, this ensures a fast and smooth shift with no noticeable interruption in propulsion.
Remanufacturing DSG7
The newer DSG 7 units required ACTRONICS to develop a dedicated remanufacturing line. The goal was to ensure that the process of the DSG 7 mechatronic units runs as efficiently as possible. In order to do so, this remanufacturing line is divided into several sub-lines: a test and control line for all incoming customer units, a line where the remanufacturing of the HCU (Hydraulic Control Unit) is carried out as a continuous process and a line where the remanufacturing of the TCU (Transmission Control Unit) is carried out.
This split remanufacturing line allows ACTRONICS the possibility to build up stock in advance. This not only makes the process much more efficient, but also ensures a shorter lead time for customers: a defective HCU can be exchanged directly with a remanufactured one from stock, meaning cars return to the road faster.
ACTRONICS Service Points
Our service point program allows private individuals access to our remanufacturing work through our wide range of Service Points. We don’t take on work from private individuals directly, only working with garages allows us to ensure that parts are fitted to an appropriate standard.
We work with independent garages as well as main dealers. Joining the ACTRONICS service point program is quick, simple and easy through you online account. The free program allows you to make potential customers aware that they can access ACTRONICS remanufacturing services via your business.
Why remanufacture?
On average, remanufactured components cost 80% less than a new replacement, save valuable resources, reduce waste and protect the environment.
ACTRONICS remanufactured parts are all supplied to be plug and play with a 2-year warranty. Over 92% of customers would recommend us, which is backed up by over 1,000 Google reviews that rate us 4.9/5!
Telephone number: 01206 849920
Email: info@actronics.co.uk
WhatsApp: +441206849920
