Installing universal standalone GCU requires certain modifications to be done to the mechatronics unit inside Getrag 6DCT470 transmission.
To modify it You’ll need:
- Soldering station
- Dremel /w abrasive plate
- Side cutters
- 1mm2 and 0,35mm2 Wires (silicone/PTFE wires, oil resistant, 200C rated)
CAUTION: This modification require soldering experience and steady hand due to very tight location of soldering
- Unscrew the plastic oil pan, keep in mind that there is a lot of transmission fluid inside.
- Remove 11 long torx screws holding the valve body.
- Remove 3 torx screws holding the main connector and unplug the small connector from the side.
- Now whole valve body should come right off.
- Flip it on the back carefully, there still should be some transmission fluid inside so its nice to put a towel under it.
- TCM is held by another 6 smaller torx screws. After removing them valve body can be put aside as it wont be needed for the modification. If You are removing the TCM to send for complete wiring service this is a final step.
- TCM is made of 3 parts held by screws and thin connector ribbons for each side.
- Remove all the screws holding it together.
- There are two plastic covers holding the ribbons down, remove them gently to fully unveil the TCU.
- Stock controller is connected to pads around it with thin aluminum wire. Remove all of them with tweezers. While removing pay attention to hold them as close to soldering pads as possible so minimal length of them remains (preferably none)
- Clean solder pads MECHANICALLY. Degreaser / nitro / acetone does not remove gel cover. Easiest way is to remove it with tweezers and ear cleaning sticks.
Connectors D and E require additional cleaning with Dremel type tool with abrasive disc to remove coating preventing soldering.
- Measure length of connecting signal (0.2mm2 or 24AWG) wires that are needed to be done. Wires shouldn’t be too short to avoid connection failure in future. Apply tin to tips of wires before soldering on to pads.
- Round connector will only be used as a passage through transmission case – please drill a hole in it and lead all the wires through it and seal it with silicone packing afterwards (f.eg.Victor Reinz Reinzosil).
- Cut the plastic cover under the round connector and remove row A with ribbon connecting it to the round connector.
Picture shows how it should look like with new wiring done.
- For C perform soldering as listed below
- C1 to D1
- C2 to D3
- C3 to GCU AN_in1 (MC1)
- C4 to GCU AN_in2 (MC2)
- C5 to GCU AN_in3 (MC3)
- C6 to D1
- C7 Leave unconnected
- C8 to D3
- C9 to GCU AN_in4 (MC4)
- C10 to D1
- C11 to GCU FREQ_in1 (MC5)
- C12 to D3
- C13 to GCU FREQ_in2 (MC7)
- C14 to D1
- C15-18 Leave unconnected
- For F perform soldering as listed below
- F1-4 to fused (25 a) +12v supply [joined with GCU_+12V_main (MC14/16)]
- F5 to GCU PWR_out1 (SV1)
- F6 to GCU PWR_out2 (SV2)
- F7-8 connect with F1-4 to fused (25 a) +12v supply
- F9 to GCU PWR_out3 (SV3)
- F10 to GCU PWR_out4 (SV4)
- F11 to GCU PWR_out5 (SV5)
- F12 to GCU PWR_out6 (SV6)
- F13 to GCU PWR_out7 (SV7)
- F14 to GCU PWR_out8 (SV8)
- F15-17 to fused (25 a) +12v supply [joined with GCU_+12V_main (MC14/16)]
- F18 to GCU PWR_out9 (SV9)
- For B perform soldering as listed below
- B1-9 Leave unconnected
- B10 to E3
- B11 to GCU FREQ_in3 (SC1)
- B12 to E1
- For D perform soldering as listed below
- D1 to E3
- D2 to GCU AN_in7 (MC10)
- D3 Already connected to C2,C8,C12 Add connection to E1 and to GCU_+5v_out (MC13)
- For E perform soldering as listed below
- E1 should be already connected to B12 and D3, add connection to +5_out (M1)
- E2 to GCU AN_in8 (MC11)
- E3 should be already connected to B10 and D1, add connection to s_GND (L2)
- After soldering ensure there are no short circuits between pads. Apply silicone seal on solder pads, and on wires to prevent them from moving around and avoid connection failure.
It is also recommended to put all wires in heat shrink sleeves inside transmission case to maximize protection
HTG GCU requires main (MAIN RELAY’ed) battery +12v applied to +12_const (M3, M4), as well as ignition +12v signal applied to +12_IGN (L1).
Even though HTG GCU has internal protection it is advised to secure IGN signal with 5Afuse to prevent failure of the device.
Ground connections GND (L3 and L4) should be made on engine or chassis, as long as chassis ground point is confirmed to be efficient.
+12v_out (M2) can be used as supply for shifter, paddles or other low power auxiliaries that needs voltage feed.
For proper functionality HTG GCU needs to be fed with ECU signals. Those signals are used to configure and map transmission operation.
To communicate with ECU AN_out1-4 (A1, A2, B1, B2) can be used and CAN_1 and CAN_2
This guide is just INFORMATIONAL one. It shows quite easy and safe method of wiring 6DCT470 transmission to work with HTG GCU, but it can be also done with different method as long as connections remain unchanged between point and GCU. .